diff --git a/launcher/BaseInstance.cpp b/launcher/BaseInstance.cpp
index 2995df6f8..a0bd88236 100644
--- a/launcher/BaseInstance.cpp
+++ b/launcher/BaseInstance.cpp
@@ -368,3 +368,8 @@ shared_qobject_ptr<LaunchTask> BaseInstance::getLaunchTask()
 {
     return m_launchProcess;
 }
+
+void BaseInstance::updateRuntimeContext()
+{
+    // NOOP
+}
diff --git a/launcher/BaseInstance.h b/launcher/BaseInstance.h
index 21cc34132..307240e0d 100644
--- a/launcher/BaseInstance.h
+++ b/launcher/BaseInstance.h
@@ -54,6 +54,7 @@
 #include "net/Mode.h"
 
 #include "minecraft/launch/MinecraftServerTarget.h"
+#include "RuntimeContext.h"
 
 class QDir;
 class Task;
@@ -220,6 +221,12 @@ public:
 
     virtual QString typeName() const = 0;
 
+    void updateRuntimeContext();
+    RuntimeContext runtimeContext() const
+    {
+        return m_runtimeContext;
+    }
+
     bool hasVersionBroken() const
     {
         return m_hasBrokenVersion;
@@ -305,6 +312,7 @@ protected: /* data */
     bool m_isRunning = false;
     shared_qobject_ptr<LaunchTask> m_launchProcess;
     QDateTime m_timeStarted;
+    RuntimeContext m_runtimeContext;
 
 private: /* data */
     Status m_status = Status::Present;
diff --git a/launcher/CMakeLists.txt b/launcher/CMakeLists.txt
index 0bdfcd44f..c58942689 100644
--- a/launcher/CMakeLists.txt
+++ b/launcher/CMakeLists.txt
@@ -26,6 +26,7 @@ set(CORE_SOURCES
     MMCZip.cpp
     MMCStrings.h
     MMCStrings.cpp
+    RuntimeContext.h
 
     # Basic instance manipulation tasks (derived from InstanceTask)
     InstanceCreationTask.h
@@ -288,8 +289,6 @@ set(MINECRAFT_SOURCES
     minecraft/Rule.h
     minecraft/OneSixVersionFormat.cpp
     minecraft/OneSixVersionFormat.h
-    minecraft/OpSys.cpp
-    minecraft/OpSys.h
     minecraft/ParseUtils.cpp
     minecraft/ParseUtils.h
     minecraft/ProfileUtils.cpp
diff --git a/launcher/NullInstance.h b/launcher/NullInstance.h
index 53e64a057..53edfa0b8 100644
--- a/launcher/NullInstance.h
+++ b/launcher/NullInstance.h
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 #include "BaseInstance.h"
 #include "launch/LaunchTask.h"
@@ -84,4 +119,8 @@ public:
     QString modsRoot() const override {
         return QString();
     }
+    void updateRuntimeContext()
+    {
+        // NOOP
+    }
 };
diff --git a/launcher/RuntimeContext.h b/launcher/RuntimeContext.h
new file mode 100644
index 000000000..c1b713187
--- /dev/null
+++ b/launcher/RuntimeContext.h
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <QSet>
+#include <QString>
+#include "settings/SettingsObject.h"
+
+struct RuntimeContext {
+    QString javaArchitecture;
+    QString javaRealArchitecture;
+    QString javaPath;
+    QString system;
+
+    QString mappedJavaRealArchitecture() const {
+        if (javaRealArchitecture == "aarch64") {
+            return "arm64";
+        }
+        return javaRealArchitecture;
+    }
+
+    void updateFromInstanceSettings(SettingsObjectPtr instanceSettings) {
+        javaArchitecture = instanceSettings->get("JavaArchitecture").toString();
+        javaRealArchitecture = instanceSettings->get("JavaRealArchitecture").toString();
+        javaPath = instanceSettings->get("JavaPath").toString();
+        system = currentSystem();
+    }
+
+    QString getClassifier() const {
+        return system + "-" + mappedJavaRealArchitecture();
+    }
+
+    // "Legacy" refers to the fact that Mojang assumed that these are the only two architectures
+    bool isLegacyArch() const {
+        QSet<QString> legacyArchitectures{"amd64", "x86_64", "i386", "i686", "x86"};
+        return legacyArchitectures.contains(mappedJavaRealArchitecture());
+    }
+
+    bool classifierMatches(QString target) const {
+        // try to match precise classifier "[os]-[arch]"
+        bool x = target == getClassifier();
+        // try to match imprecise classifier on legacy architectures "[os]"
+        if (!x && isLegacyArch())
+            x = target == system;
+
+        return x;
+    }
+
+    static QString currentSystem() {
+#if defined(Q_OS_LINUX)
+        return "linux";
+#elif defined(Q_OS_MACOS)
+        return "osx";
+#elif defined(Q_OS_WINDOWS)
+        return "windows";
+#elif defined(Q_OS_FREEBSD)
+        return "freebsd";
+#elif defined(Q_OS_OPENBSD)
+        return "openbsd";
+#else
+        return "unknown";
+#endif
+    }
+};
diff --git a/launcher/launch/steps/CheckJava.cpp b/launcher/launch/steps/CheckJava.cpp
index db56b652c..7aeb61bf7 100644
--- a/launcher/launch/steps/CheckJava.cpp
+++ b/launcher/launch/steps/CheckJava.cpp
@@ -121,7 +121,6 @@ void CheckJava::checkJavaFinished(JavaCheckResult result)
             emit logLine(QString("Could not start java:"), MessageLevel::Error);
             emit logLines(result.errorLog.split('\n'), MessageLevel::Error);
             emit logLine(QString("\nCheck your Java settings."), MessageLevel::Launcher);
-            printSystemInfo(false, false);
             emitFailed(QString("Could not start java!"));
             return;
         }
@@ -130,7 +129,6 @@ void CheckJava::checkJavaFinished(JavaCheckResult result)
             emit logLine(QString("Java checker returned some invalid data we don't understand:"), MessageLevel::Error);
             emit logLines(result.outLog.split('\n'), MessageLevel::Warning);
             emit logLine("\nMinecraft might not start properly.", MessageLevel::Launcher);
-            printSystemInfo(false, false);
             emitSucceeded();
             return;
         }
@@ -138,7 +136,6 @@ void CheckJava::checkJavaFinished(JavaCheckResult result)
         {
             auto instance = m_parent->instance();
             printJavaInfo(result.javaVersion.toString(), result.mojangPlatform, result.realPlatform, result.javaVendor);
-            printSystemInfo(true, result.is_64bit);
             instance->settings()->set("JavaVersion", result.javaVersion.toString());
             instance->settings()->set("JavaArchitecture", result.mojangPlatform);
             instance->settings()->set("JavaRealArchitecture", result.realPlatform);
@@ -155,20 +152,3 @@ void CheckJava::printJavaInfo(const QString& version, const QString& architectur
     emit logLine(QString("Java is version %1, using %2 (%3) architecture, from %4.\n\n")
                     .arg(version, architecture, realArchitecture, vendor), MessageLevel::Launcher);
 }
-
-void CheckJava::printSystemInfo(bool javaIsKnown, bool javaIs64bit)
-{
-    auto cpu64 = Sys::isCPU64bit();
-    auto system64 = Sys::isSystem64bit();
-    if(cpu64 != system64)
-    {
-        emit logLine(QString("Your CPU architecture is not matching your system architecture. You might want to install a 64bit Operating System.\n\n"), MessageLevel::Error);
-    }
-    if(javaIsKnown)
-    {
-        if(javaIs64bit != system64)
-        {
-            emit logLine(QString("Your Java architecture is not matching your system architecture. You might want to install a 64bit Java version.\n\n"), MessageLevel::Error);
-        }
-    }
-}
diff --git a/launcher/minecraft/Component.cpp b/launcher/minecraft/Component.cpp
index c7dd5e36d..7e5b60589 100644
--- a/launcher/minecraft/Component.cpp
+++ b/launcher/minecraft/Component.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include <meta/VersionList.h>
 #include <meta/Index.h>
 #include "Component.h"
@@ -60,7 +95,7 @@ void Component::applyTo(LaunchProfile* profile)
     auto vfile = getVersionFile();
     if(vfile)
     {
-        vfile->applyTo(profile);
+        vfile->applyTo(profile, m_parent->runtimeContext());
     }
     else
     {
diff --git a/launcher/minecraft/LaunchProfile.cpp b/launcher/minecraft/LaunchProfile.cpp
index 39a342ca9..9a6cea11a 100644
--- a/launcher/minecraft/LaunchProfile.cpp
+++ b/launcher/minecraft/LaunchProfile.cpp
@@ -173,9 +173,9 @@ void LaunchProfile::applyCompatibleJavaMajors(QList<int>& javaMajor)
     m_compatibleJavaMajors.append(javaMajor);
 }
 
-void LaunchProfile::applyLibrary(LibraryPtr library)
+void LaunchProfile::applyLibrary(LibraryPtr library, const RuntimeContext & runtimeContext)
 {
-    if(!library->isActive())
+    if(!library->isActive(runtimeContext))
     {
         return;
     }
@@ -205,9 +205,9 @@ void LaunchProfile::applyLibrary(LibraryPtr library)
     }
 }
 
-void LaunchProfile::applyMavenFile(LibraryPtr mavenFile)
+void LaunchProfile::applyMavenFile(LibraryPtr mavenFile, const RuntimeContext & runtimeContext)
 {
-    if(!mavenFile->isActive())
+    if(!mavenFile->isActive(runtimeContext))
     {
         return;
     }
@@ -221,10 +221,10 @@ void LaunchProfile::applyMavenFile(LibraryPtr mavenFile)
     m_mavenFiles.append(Library::limitedCopy(mavenFile));
 }
 
-void LaunchProfile::applyAgent(AgentPtr agent)
+void LaunchProfile::applyAgent(AgentPtr agent, const RuntimeContext & runtimeContext)
 {
     auto lib = agent->library();
-    if(!lib->isActive())
+    if(!lib->isActive(runtimeContext))
     {
         return;
     }
@@ -354,7 +354,7 @@ const QList<int> & LaunchProfile::getCompatibleJavaMajors() const
 }
 
 void LaunchProfile::getLibraryFiles(
-    const QString& architecture,
+    const RuntimeContext & runtimeContext,
     QStringList& jars,
     QStringList& nativeJars,
     const QString& overridePath,
@@ -366,7 +366,7 @@ void LaunchProfile::getLibraryFiles(
     nativeJars.clear();
     for (auto lib : getLibraries())
     {
-        lib->getApplicableFiles(currentSystem, jars, nativeJars, native32, native64, overridePath);
+        lib->getApplicableFiles(runtimeContext, jars, nativeJars, native32, native64, overridePath);
     }
     // NOTE: order is important here, add main jar last to the lists
     if(m_mainJar)
@@ -379,18 +379,18 @@ void LaunchProfile::getLibraryFiles(
         }
         else
         {
-            m_mainJar->getApplicableFiles(currentSystem, jars, nativeJars, native32, native64, overridePath);
+            m_mainJar->getApplicableFiles(runtimeContext, jars, nativeJars, native32, native64, overridePath);
         }
     }
     for (auto lib : getNativeLibraries())
     {
-        lib->getApplicableFiles(currentSystem, jars, nativeJars, native32, native64, overridePath);
+        lib->getApplicableFiles(runtimeContext, jars, nativeJars, native32, native64, overridePath);
     }
-    if(architecture == "32")
+    if(runtimeContext.javaArchitecture == "32")
     {
         nativeJars.append(native32);
     }
-    else if(architecture == "64")
+    else if(runtimeContext.javaArchitecture == "64")
     {
         nativeJars.append(native64);
     }
diff --git a/launcher/minecraft/LaunchProfile.h b/launcher/minecraft/LaunchProfile.h
index b55cf6615..49c1217d3 100644
--- a/launcher/minecraft/LaunchProfile.h
+++ b/launcher/minecraft/LaunchProfile.h
@@ -56,9 +56,9 @@ public: /* application of profile variables from patches */
     void applyTweakers(const QStringList &tweakers);
     void applyJarMods(const QList<LibraryPtr> &jarMods);
     void applyMods(const QList<LibraryPtr> &jarMods);
-    void applyLibrary(LibraryPtr library);
-    void applyMavenFile(LibraryPtr library);
-    void applyAgent(AgentPtr agent);
+    void applyLibrary(LibraryPtr library, const RuntimeContext & runtimeContext);
+    void applyMavenFile(LibraryPtr library, const RuntimeContext & runtimeContext);
+    void applyAgent(AgentPtr agent, const RuntimeContext & runtimeContext);
     void applyCompatibleJavaMajors(QList<int>& javaMajor);
     void applyMainJar(LibraryPtr jar);
     void applyProblemSeverity(ProblemSeverity severity);
@@ -83,7 +83,7 @@ public: /* getters for profile variables */
     const QList<int> & getCompatibleJavaMajors() const;
     const LibraryPtr getMainJar() const;
     void getLibraryFiles(
-        const QString & architecture,
+        const RuntimeContext & runtimeContext,
         QStringList & jars,
         QStringList & nativeJars,
         const QString & overridePath,
diff --git a/launcher/minecraft/Library.cpp b/launcher/minecraft/Library.cpp
index ba7aed4b5..cb2b5254d 100644
--- a/launcher/minecraft/Library.cpp
+++ b/launcher/minecraft/Library.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "Library.h"
 #include "MinecraftInstance.h"
 
@@ -7,7 +42,7 @@
 #include <BuildConfig.h>
 
 
-void Library::getApplicableFiles(OpSys system, QStringList& jar, QStringList& native, QStringList& native32,
+void Library::getApplicableFiles(const RuntimeContext & runtimeContext, QStringList& jar, QStringList& native, QStringList& native32,
                                  QStringList& native64, const QString &overridePath) const
 {
     bool local = isLocal();
@@ -21,7 +56,7 @@ void Library::getApplicableFiles(OpSys system, QStringList& jar, QStringList& na
         }
         return out.absoluteFilePath();
     };
-    QString raw_storage = storageSuffix(system);
+    QString raw_storage = storageSuffix(runtimeContext);
     if(isNative())
     {
         if (raw_storage.contains("${arch}"))
@@ -45,7 +80,7 @@ void Library::getApplicableFiles(OpSys system, QStringList& jar, QStringList& na
 }
 
 QList<NetAction::Ptr> Library::getDownloads(
-    OpSys system,
+    const RuntimeContext & runtimeContext,
     class HttpMetaCache* cache,
     QStringList& failedLocalFiles,
     const QString & overridePath
@@ -107,14 +142,14 @@ QList<NetAction::Ptr> Library::getDownloads(
         return true;
     };
 
-    QString raw_storage = storageSuffix(system);
+    QString raw_storage = storageSuffix(runtimeContext);
     if(m_mojangDownloads)
     {
         if(isNative())
         {
-            if(m_nativeClassifiers.contains(system))
+            auto nativeClassifier = getCompatibleNative(runtimeContext);
+            if(!nativeClassifier.isNull())
             {
-                auto nativeClassifier = m_nativeClassifiers[system];
                 if(nativeClassifier.contains("${arch}"))
                 {
                     auto nat32Classifier = nativeClassifier;
@@ -203,7 +238,7 @@ QList<NetAction::Ptr> Library::getDownloads(
     return out;
 }
 
-bool Library::isActive() const
+bool Library::isActive(const RuntimeContext & runtimeContext) const
 {
     bool result = true;
     if (m_rules.empty())
@@ -215,7 +250,7 @@ bool Library::isActive() const
         RuleAction ruleResult = Disallow;
         for (auto rule : m_rules)
         {
-            RuleAction temp = rule->apply(this);
+            RuleAction temp = rule->apply(this, runtimeContext);
             if (temp != Defer)
                 ruleResult = temp;
         }
@@ -223,7 +258,7 @@ bool Library::isActive() const
     }
     if (isNative())
     {
-        result = result && m_nativeClassifiers.contains(currentSystem);
+        result = result && !getCompatibleNative(runtimeContext).isNull();
     }
     return result;
 }
@@ -238,6 +273,19 @@ bool Library::isAlwaysStale() const
     return m_hint == "always-stale";
 }
 
+QString Library::getCompatibleNative(const RuntimeContext & runtimeContext) const {
+    // try to match precise classifier "[os]-[arch]"
+    auto entry = m_nativeClassifiers.constFind(runtimeContext.getClassifier());
+    // try to match imprecise classifier on legacy architectures "[os]"
+    if (entry == m_nativeClassifiers.constEnd() && runtimeContext.isLegacyArch())
+        entry = m_nativeClassifiers.constFind(runtimeContext.system);
+
+    if (entry == m_nativeClassifiers.constEnd())
+        return QString();
+
+    return entry.value();
+}
+
 void Library::setStoragePrefix(QString prefix)
 {
     m_storagePrefix = prefix;
@@ -257,7 +305,7 @@ QString Library::storagePrefix() const
     return m_storagePrefix;
 }
 
-QString Library::filename(OpSys system) const
+QString Library::filename(const RuntimeContext & runtimeContext) const
 {
     if(!m_filename.isEmpty())
     {
@@ -271,9 +319,10 @@ QString Library::filename(OpSys system) const
 
     // otherwise native, override classifiers. Mojang HACK!
     GradleSpecifier nativeSpec = m_name;
-    if (m_nativeClassifiers.contains(system))
+    QString nativeClassifier = getCompatibleNative(runtimeContext);
+    if (!nativeClassifier.isNull())
     {
-        nativeSpec.setClassifier(m_nativeClassifiers[system]);
+        nativeSpec.setClassifier(nativeClassifier);
     }
     else
     {
@@ -282,14 +331,14 @@ QString Library::filename(OpSys system) const
     return nativeSpec.getFileName();
 }
 
-QString Library::displayName(OpSys system) const
+QString Library::displayName(const RuntimeContext & runtimeContext) const
 {
     if(!m_displayname.isEmpty())
         return m_displayname;
-    return filename(system);
+    return filename(runtimeContext);
 }
 
-QString Library::storageSuffix(OpSys system) const
+QString Library::storageSuffix(const RuntimeContext & runtimeContext) const
 {
     // non-native? use only the gradle specifier
     if (!isNative())
@@ -299,9 +348,10 @@ QString Library::storageSuffix(OpSys system) const
 
     // otherwise native, override classifiers. Mojang HACK!
     GradleSpecifier nativeSpec = m_name;
-    if (m_nativeClassifiers.contains(system))
+    QString nativeClassifier = getCompatibleNative(runtimeContext);
+    if (!nativeClassifier.isNull())
     {
-        nativeSpec.setClassifier(m_nativeClassifiers[system]);
+        nativeSpec.setClassifier(nativeClassifier);
     }
     else
     {
diff --git a/launcher/minecraft/Library.h b/launcher/minecraft/Library.h
index 0740a7ca2..950aec9d7 100644
--- a/launcher/minecraft/Library.h
+++ b/launcher/minecraft/Library.h
@@ -1,8 +1,44 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 #include <QString>
 #include <net/NetAction.h>
 #include <QPair>
 #include <QList>
+#include <QString>
 #include <QStringList>
 #include <QMap>
 #include <QDir>
@@ -10,9 +46,9 @@
 #include <memory>
 
 #include "Rule.h"
-#include "minecraft/OpSys.h"
 #include "GradleSpecifier.h"
 #include "MojangDownloadInfo.h"
+#include "RuntimeContext.h"
 
 class Library;
 class MinecraftInstance;
@@ -98,7 +134,7 @@ public: /* methods */
         m_repositoryURL = base_url;
     }
 
-    void getApplicableFiles(OpSys system, QStringList & jar, QStringList & native,
+    void getApplicableFiles(const RuntimeContext & runtimeContext, QStringList & jar, QStringList & native,
                             QStringList & native32, QStringList & native64, const QString & overridePath) const;
 
     void setAbsoluteUrl(const QString &absolute_url)
@@ -112,7 +148,7 @@ public: /* methods */
     }
 
     /// Get the file name of the library
-    QString filename(OpSys system) const;
+    QString filename(const RuntimeContext & runtimeContext) const;
 
     // DEPRECATED: set a display name, used by jar mods only
     void setDisplayName(const QString & displayName)
@@ -121,7 +157,7 @@ public: /* methods */
     }
 
     /// Get the file name of the library
-    QString displayName(OpSys system) const;
+    QString displayName(const RuntimeContext & runtimeContext) const;
 
     void setMojangDownloadInfo(MojangLibraryDownloadInfo::Ptr info)
     {
@@ -140,7 +176,7 @@ public: /* methods */
     }
 
     /// Returns true if the library should be loaded (or extracted, in case of natives)
-    bool isActive() const;
+    bool isActive(const RuntimeContext & runtimeContext) const;
 
     /// Returns true if the library is contained in an instance and false if it is shared
     bool isLocal() const;
@@ -152,9 +188,11 @@ public: /* methods */
     bool isForge() const;
 
     // Get a list of downloads for this library
-    QList<NetAction::Ptr> getDownloads(OpSys system, class HttpMetaCache * cache,
+    QList<NetAction::Ptr> getDownloads(const RuntimeContext & runtimeContext, class HttpMetaCache * cache,
                                      QStringList & failedLocalFiles, const QString & overridePath) const;
 
+    QString getCompatibleNative(const RuntimeContext & runtimeContext) const;
+
 private: /* methods */
     /// the default storage prefix used by PolyMC
     static QString defaultStoragePrefix();
@@ -163,7 +201,7 @@ private: /* methods */
     QString storagePrefix() const;
 
     /// Get the relative file path where the library should be saved
-    QString storageSuffix(OpSys system) const;
+    QString storageSuffix(const RuntimeContext & runtimeContext) const;
 
     QString hint() const
     {
@@ -204,7 +242,7 @@ protected: /* data */
     QStringList m_extractExcludes;
 
     /// native suffixes per OS
-    QMap<OpSys, QString> m_nativeClassifiers;
+    QMap<QString, QString> m_nativeClassifiers;
 
     /// true if the library had a rules section (even empty)
     bool applyRules = false;
diff --git a/launcher/minecraft/MinecraftInstance.cpp b/launcher/minecraft/MinecraftInstance.cpp
index 62540c757..3a820951b 100644
--- a/launcher/minecraft/MinecraftInstance.cpp
+++ b/launcher/minecraft/MinecraftInstance.cpp
@@ -147,6 +147,7 @@ void MinecraftInstance::loadSpecificSettings()
         m_settings->registerPassthrough(global_settings->getSetting("JavaTimestamp"), javaOrLocation);
         m_settings->registerPassthrough(global_settings->getSetting("JavaVersion"), javaOrLocation);
         m_settings->registerPassthrough(global_settings->getSetting("JavaArchitecture"), javaOrLocation);
+        m_settings->registerPassthrough(global_settings->getSetting("JavaRealArchitecture"), javaOrLocation);
 
         // Window Size
         auto windowSetting = m_settings->registerSetting("OverrideWindow", false);
@@ -190,6 +191,13 @@ void MinecraftInstance::loadSpecificSettings()
     qDebug() << "Instance-type specific settings were loaded!";
 
     setSpecificSettingsLoaded(true);
+
+    updateRuntimeContext();
+}
+
+void MinecraftInstance::updateRuntimeContext()
+{
+    m_runtimeContext.updateFromInstanceSettings(m_settings);
 }
 
 QString MinecraftInstance::typeName() const
@@ -327,9 +335,8 @@ QDir MinecraftInstance::versionsPath() const
 QStringList MinecraftInstance::getClassPath()
 {
     QStringList jars, nativeJars;
-    auto javaArchitecture = settings()->get("JavaArchitecture").toString();
     auto profile = m_components->getProfile();
-    profile->getLibraryFiles(javaArchitecture, jars, nativeJars, getLocalLibraryPath(), binRoot());
+    profile->getLibraryFiles(runtimeContext(), jars, nativeJars, getLocalLibraryPath(), binRoot());
     return jars;
 }
 
@@ -342,9 +349,8 @@ QString MinecraftInstance::getMainClass() const
 QStringList MinecraftInstance::getNativeJars()
 {
     QStringList jars, nativeJars;
-    auto javaArchitecture = settings()->get("JavaArchitecture").toString();
     auto profile = m_components->getProfile();
-    profile->getLibraryFiles(javaArchitecture, jars, nativeJars, getLocalLibraryPath(), binRoot());
+    profile->getLibraryFiles(runtimeContext(), jars, nativeJars, getLocalLibraryPath(), binRoot());
     return nativeJars;
 }
 
@@ -368,7 +374,7 @@ QStringList MinecraftInstance::extraArguments()
     for (auto agent : agents)
     {
         QStringList jar, temp1, temp2, temp3;
-        agent->library()->getApplicableFiles(currentSystem, jar, temp1, temp2, temp3, getLocalLibraryPath());
+        agent->library()->getApplicableFiles(runtimeContext(), jar, temp1, temp2, temp3, getLocalLibraryPath());
         list.append("-javaagent:"+jar[0]+(agent->argument().isEmpty() ? "" : "="+agent->argument()));
     }
     return list;
@@ -625,8 +631,7 @@ QString MinecraftInstance::createLaunchScript(AuthSessionPtr session, MinecraftS
     // libraries and class path.
     {
         QStringList jars, nativeJars;
-        auto javaArchitecture = settings()->get("JavaArchitecture").toString();
-        profile->getLibraryFiles(javaArchitecture, jars, nativeJars, getLocalLibraryPath(), binRoot());
+        profile->getLibraryFiles(runtimeContext(), jars, nativeJars, getLocalLibraryPath(), binRoot());
         for(auto file: jars)
         {
             launchScript += "cp " + file + "\n";
@@ -682,8 +687,7 @@ QStringList MinecraftInstance::verboseDescription(AuthSessionPtr session, Minecr
     {
         out << "Libraries:";
         QStringList jars, nativeJars;
-        auto javaArchitecture = settings->get("JavaArchitecture").toString();
-        profile->getLibraryFiles(javaArchitecture, jars, nativeJars, getLocalLibraryPath(), binRoot());
+        profile->getLibraryFiles(runtimeContext(), jars, nativeJars, getLocalLibraryPath(), binRoot());
         auto printLibFile = [&](const QString & path)
         {
             QFileInfo info(path);
@@ -748,8 +752,8 @@ QStringList MinecraftInstance::verboseDescription(AuthSessionPtr session, Minecr
         out << "Jar Mods:";
         for(auto & jarmod: jarMods)
         {
-            auto displayname = jarmod->displayName(currentSystem);
-            auto realname = jarmod->filename(currentSystem);
+            auto displayname = jarmod->displayName(runtimeContext());
+            auto realname = jarmod->filename(runtimeContext());
             if(displayname != realname)
             {
                 out << "  " + displayname + " (" + realname + ")";
@@ -911,6 +915,7 @@ QString MinecraftInstance::getStatusbarDescription()
 
 Task::Ptr MinecraftInstance::createUpdateTask(Net::Mode mode)
 {
+    updateRuntimeContext();
     switch (mode)
     {
         case Net::Mode::Offline:
@@ -927,6 +932,7 @@ Task::Ptr MinecraftInstance::createUpdateTask(Net::Mode mode)
 
 shared_qobject_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin)
 {
+    updateRuntimeContext();
     // FIXME: get rid of shared_from_this ...
     auto process = LaunchTask::create(std::dynamic_pointer_cast<MinecraftInstance>(shared_from_this()));
     auto pptr = process.get();
@@ -1157,7 +1163,7 @@ QList<Mod*> MinecraftInstance::getJarMods() const
     for (auto jarmod : profile->getJarMods())
     {
         QStringList jar, temp1, temp2, temp3;
-        jarmod->getApplicableFiles(currentSystem, jar, temp1, temp2, temp3, jarmodsPath().absolutePath());
+        jarmod->getApplicableFiles(runtimeContext(), jar, temp1, temp2, temp3, jarmodsPath().absolutePath());
         // QString filePath = jarmodsPath().absoluteFilePath(jarmod->filename(currentSystem));
         mods.push_back(new Mod(QFileInfo(jar[0])));
     }
diff --git a/launcher/minecraft/MinecraftInstance.h b/launcher/minecraft/MinecraftInstance.h
index fe39674a6..1895d1879 100644
--- a/launcher/minecraft/MinecraftInstance.h
+++ b/launcher/minecraft/MinecraftInstance.h
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 #include "BaseInstance.h"
 #include <java/JavaVersion.h>
@@ -72,6 +107,8 @@ public:
     /** Returns whether the instance, with its version, has support for demo mode. */
     [[nodiscard]] bool supportsDemo() const;
 
+    void updateRuntimeContext();
+
     //////  Profile management //////
     std::shared_ptr<PackProfile> getPackProfile() const;
 
diff --git a/launcher/minecraft/MojangVersionFormat.cpp b/launcher/minecraft/MojangVersionFormat.cpp
index 94c586762..e00d2c6ea 100644
--- a/launcher/minecraft/MojangVersionFormat.cpp
+++ b/launcher/minecraft/MojangVersionFormat.cpp
@@ -362,11 +362,8 @@ LibraryPtr MojangVersionFormat::libraryFromJson(ProblemContainer & problems, con
             {
                 qWarning() << filename << "contains an invalid native (skipping)";
             }
-            OpSys opSys = OpSys_fromString(it.key());
-            if (opSys != Os_Other)
-            {
-                out->m_nativeClassifiers[opSys] = it.value().toString();
-            }
+            // FIXME: Skip unknown platforms
+            out->m_nativeClassifiers[it.key()] = it.value().toString();
         }
     }
     if (libObj.contains("rules"))
@@ -395,7 +392,7 @@ QJsonObject MojangVersionFormat::libraryToJson(Library *library)
         auto iter = library->m_nativeClassifiers.begin();
         while (iter != library->m_nativeClassifiers.end())
         {
-            nativeList.insert(OpSys_toString(iter.key()), iter.value());
+            nativeList.insert(iter.key(), iter.value());
             iter++;
         }
         libRoot.insert("natives", nativeList);
diff --git a/launcher/minecraft/OpSys.cpp b/launcher/minecraft/OpSys.cpp
deleted file mode 100644
index 093ec4190..000000000
--- a/launcher/minecraft/OpSys.cpp
+++ /dev/null
@@ -1,46 +0,0 @@
-/* Copyright 2013-2021 MultiMC Contributors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "OpSys.h"
-
-OpSys OpSys_fromString(QString name)
-{
-    if (name == "freebsd")
-        return Os_FreeBSD;
-    if (name == "linux")
-        return Os_Linux;
-    if (name == "windows")
-        return Os_Windows;
-    if (name == "osx")
-        return Os_OSX;
-    return Os_Other;
-}
-
-QString OpSys_toString(OpSys name)
-{
-    switch (name)
-    {
-    case Os_FreeBSD:
-	return "freebsd";
-    case Os_Linux:
-        return "linux";
-    case Os_OSX:
-        return "osx";
-    case Os_Windows:
-        return "windows";
-    default:
-        return "other";
-    }
-}
\ No newline at end of file
diff --git a/launcher/minecraft/OpSys.h b/launcher/minecraft/OpSys.h
deleted file mode 100644
index 0936f8174..000000000
--- a/launcher/minecraft/OpSys.h
+++ /dev/null
@@ -1,38 +0,0 @@
-/* Copyright 2013-2021 MultiMC Contributors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-#include <QString>
-enum OpSys
-{
-    Os_Windows,
-    Os_FreeBSD,
-    Os_Linux,
-    Os_OSX,
-    Os_Other
-};
-
-OpSys OpSys_fromString(QString);
-QString OpSys_toString(OpSys);
-
-#ifdef Q_OS_WIN32
-    #define currentSystem Os_Windows
-#elif defined Q_OS_MAC
-    #define currentSystem Os_OSX
-#elif defined Q_OS_FREEBSD
-    #define currentSystem Os_FreeBSD
-#else
-    #define currentSystem Os_Linux
-#endif
diff --git a/launcher/minecraft/PackProfile.cpp b/launcher/minecraft/PackProfile.cpp
index 5e76b892a..1618458f5 100644
--- a/launcher/minecraft/PackProfile.cpp
+++ b/launcher/minecraft/PackProfile.cpp
@@ -273,6 +273,11 @@ void PackProfile::scheduleSave()
     d->m_saveTimer.start();
 }
 
+RuntimeContext PackProfile::runtimeContext()
+{
+    return d->m_instance->runtimeContext();
+}
+
 QString PackProfile::componentsFilePath() const
 {
     return FS::PathCombine(d->m_instance->instanceRoot(), "mmc-pack.json");
@@ -784,7 +789,7 @@ bool PackProfile::removeComponent_internal(ComponentPtr patch)
             return true;
         }
         QStringList jar, temp1, temp2, temp3;
-        jarMod->getApplicableFiles(currentSystem, jar, temp1, temp2, temp3, d->m_instance->jarmodsPath().absolutePath());
+        jarMod->getApplicableFiles(d->m_instance->runtimeContext(), jar, temp1, temp2, temp3, d->m_instance->jarmodsPath().absolutePath());
         QFileInfo finfo (jar[0]);
         if(finfo.exists())
         {
diff --git a/launcher/minecraft/PackProfile.h b/launcher/minecraft/PackProfile.h
index 918e7f7ad..807511a26 100644
--- a/launcher/minecraft/PackProfile.h
+++ b/launcher/minecraft/PackProfile.h
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #pragma once
@@ -104,6 +124,9 @@ public:
     /// if there is a save scheduled, do it now.
     void saveNow();
 
+    /// helper method, returns RuntimeContext of instance
+    RuntimeContext runtimeContext();
+
 signals:
     void minecraftChanged();
 
diff --git a/launcher/minecraft/Rule.cpp b/launcher/minecraft/Rule.cpp
index af2861e37..ff3d75f2e 100644
--- a/launcher/minecraft/Rule.cpp
+++ b/launcher/minecraft/Rule.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QJsonObject>
@@ -60,10 +80,10 @@ QList<std::shared_ptr<Rule>> rulesFromJsonV4(const QJsonObject &objectWithRules)
         auto osNameVal = osObj.value("name");
         if (!osNameVal.isString())
             continue;
-        OpSys requiredOs = OpSys_fromString(osNameVal.toString());
+        QString osName = osNameVal.toString();
         QString versionRegex = osObj.value("version").toString();
         // add a new OS rule
-        rules.append(OsRule::create(action, requiredOs, versionRegex));
+        rules.append(OsRule::create(action, osName, versionRegex));
     }
     return rules;
 }
@@ -81,7 +101,7 @@ QJsonObject OsRule::toJson()
     ruleObj.insert("action", m_result == Allow ? QString("allow") : QString("disallow"));
     QJsonObject osObj;
     {
-        osObj.insert("name", OpSys_toString(m_system));
+        osObj.insert("name", m_system);
         if(!m_version_regexp.isEmpty())
         {
             osObj.insert("version", m_version_regexp);
diff --git a/launcher/minecraft/Rule.h b/launcher/minecraft/Rule.h
index 7aa34d967..236f9a878 100644
--- a/launcher/minecraft/Rule.h
+++ b/launcher/minecraft/Rule.h
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #pragma once
@@ -19,7 +39,7 @@
 #include <QList>
 #include <QJsonObject>
 #include <memory>
-#include "OpSys.h"
+#include "RuntimeContext.h"
 
 class Library;
 class Rule;
@@ -37,7 +57,7 @@ class Rule
 {
 protected:
     RuleAction m_result;
-    virtual bool applies(const Library *parent) = 0;
+    virtual bool applies(const Library *parent, const RuntimeContext & runtimeContext) = 0;
 
 public:
     Rule(RuleAction result) : m_result(result)
@@ -45,9 +65,9 @@ public:
     }
     virtual ~Rule() {};
     virtual QJsonObject toJson() = 0;
-    RuleAction apply(const Library *parent)
+    RuleAction apply(const Library *parent, const RuntimeContext & runtimeContext)
     {
-        if (applies(parent))
+        if (applies(parent, runtimeContext))
             return m_result;
         else
             return Defer;
@@ -58,23 +78,23 @@ class OsRule : public Rule
 {
 private:
     // the OS
-    OpSys m_system;
+    QString m_system;
     // the OS version regexp
     QString m_version_regexp;
 
 protected:
-    virtual bool applies(const Library *)
+    virtual bool applies(const Library *, const RuntimeContext & runtimeContext)
     {
-        return (m_system == currentSystem);
+        return runtimeContext.classifierMatches(m_system);
     }
-    OsRule(RuleAction result, OpSys system, QString version_regexp)
+    OsRule(RuleAction result, QString system, QString version_regexp)
         : Rule(result), m_system(system), m_version_regexp(version_regexp)
     {
     }
 
 public:
     virtual QJsonObject toJson();
-    static std::shared_ptr<OsRule> create(RuleAction result, OpSys system,
+    static std::shared_ptr<OsRule> create(RuleAction result, QString system,
                                           QString version_regexp)
     {
         return std::shared_ptr<OsRule>(new OsRule(result, system, version_regexp));
@@ -84,7 +104,7 @@ public:
 class ImplicitRule : public Rule
 {
 protected:
-    virtual bool applies(const Library *)
+    virtual bool applies(const Library *, const RuntimeContext & runtimeContext)
     {
         return true;
     }
diff --git a/launcher/minecraft/VersionFile.cpp b/launcher/minecraft/VersionFile.cpp
index a9a0f7f4b..76f41600f 100644
--- a/launcher/minecraft/VersionFile.cpp
+++ b/launcher/minecraft/VersionFile.cpp
@@ -51,7 +51,7 @@ static bool isMinecraftVersion(const QString &uid)
     return uid == "net.minecraft";
 }
 
-void VersionFile::applyTo(LaunchProfile *profile)
+void VersionFile::applyTo(LaunchProfile *profile, const RuntimeContext & runtimeContext)
 {
     // Only real Minecraft can set those. Don't let anything override them.
     if (isMinecraftVersion(uid))
@@ -77,15 +77,15 @@ void VersionFile::applyTo(LaunchProfile *profile)
 
     for (auto library : libraries)
     {
-        profile->applyLibrary(library);
+        profile->applyLibrary(library, runtimeContext);
     }
     for (auto mavenFile : mavenFiles)
     {
-        profile->applyMavenFile(mavenFile);
+        profile->applyMavenFile(mavenFile, runtimeContext);
     }
     for (auto agent : agents)
     {
-        profile->applyAgent(agent);
+        profile->applyAgent(agent, runtimeContext);
     }
     profile->applyProblemSeverity(getProblemSeverity());
 }
diff --git a/launcher/minecraft/VersionFile.h b/launcher/minecraft/VersionFile.h
index d4b29719a..e1b62f6a4 100644
--- a/launcher/minecraft/VersionFile.h
+++ b/launcher/minecraft/VersionFile.h
@@ -41,7 +41,6 @@
 #include <QSet>
 
 #include <memory>
-#include "minecraft/OpSys.h"
 #include "minecraft/Rule.h"
 #include "ProblemProvider.h"
 #include "Library.h"
@@ -60,7 +59,7 @@ class VersionFile : public ProblemContainer
     friend class MojangVersionFormat;
     friend class OneSixVersionFormat;
 public: /* methods */
-    void applyTo(LaunchProfile* profile);
+    void applyTo(LaunchProfile* profile, const RuntimeContext & runtimeContext);
 
 public: /* data */
     /// PolyMC: order hint for this version file if no explicit order is set
diff --git a/launcher/minecraft/launch/ModMinecraftJar.cpp b/launcher/minecraft/launch/ModMinecraftJar.cpp
index 93de9d59a..1d6eecf2d 100644
--- a/launcher/minecraft/launch/ModMinecraftJar.cpp
+++ b/launcher/minecraft/launch/ModMinecraftJar.cpp
@@ -1,22 +1,41 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "ModMinecraftJar.h"
 #include "launch/LaunchTask.h"
 #include "MMCZip.h"
-#include "minecraft/OpSys.h"
 #include "FileSystem.h"
 #include "minecraft/MinecraftInstance.h"
 #include "minecraft/PackProfile.h"
@@ -50,7 +69,7 @@ void ModMinecraftJar::executeTask()
     {
         auto mainJar = profile->getMainJar();
         QStringList jars, temp1, temp2, temp3, temp4;
-        mainJar->getApplicableFiles(currentSystem, jars, temp1, temp2, temp3, m_inst->getLocalLibraryPath());
+        mainJar->getApplicableFiles(m_inst->runtimeContext(), jars, temp1, temp2, temp3, m_inst->getLocalLibraryPath());
         auto sourceJarPath = jars[0];
         if(!MMCZip::createModdedJar(sourceJarPath, finalJarPath, jarMods))
         {
diff --git a/launcher/minecraft/launch/ScanModFolders.cpp b/launcher/minecraft/launch/ScanModFolders.cpp
index 2a0e21b39..bdffeaddd 100644
--- a/launcher/minecraft/launch/ScanModFolders.cpp
+++ b/launcher/minecraft/launch/ScanModFolders.cpp
@@ -1,22 +1,41 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "ScanModFolders.h"
 #include "launch/LaunchTask.h"
 #include "MMCZip.h"
-#include "minecraft/OpSys.h"
 #include "FileSystem.h"
 #include "minecraft/MinecraftInstance.h"
 #include "minecraft/mod/ModFolderModel.h"
diff --git a/launcher/minecraft/update/FoldersTask.cpp b/launcher/minecraft/update/FoldersTask.cpp
index 22768bd97..b9ee9d980 100644
--- a/launcher/minecraft/update/FoldersTask.cpp
+++ b/launcher/minecraft/update/FoldersTask.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "FoldersTask.h"
 #include "minecraft/MinecraftInstance.h"
 #include <QDir>
diff --git a/launcher/minecraft/update/LibrariesTask.cpp b/launcher/minecraft/update/LibrariesTask.cpp
index aa2bf4074..3b129fe11 100644
--- a/launcher/minecraft/update/LibrariesTask.cpp
+++ b/launcher/minecraft/update/LibrariesTask.cpp
@@ -34,7 +34,7 @@ void LibrariesTask::executeTask()
                 emitFailed(tr("Null jar is specified in the metadata, aborting."));
                 return false;
             }
-            auto dls = lib->getDownloads(currentSystem, metacache.get(), errors, localPath);
+            auto dls = lib->getDownloads(inst->runtimeContext(), metacache.get(), errors, localPath);
             for(auto dl : dls)
             {
                 downloadJob->addNetAction(dl);
diff --git a/launcher/ui/pages/instance/InstanceSettingsPage.cpp b/launcher/ui/pages/instance/InstanceSettingsPage.cpp
index 03910745f..5da7f19f5 100644
--- a/launcher/ui/pages/instance/InstanceSettingsPage.cpp
+++ b/launcher/ui/pages/instance/InstanceSettingsPage.cpp
@@ -274,6 +274,9 @@ void InstanceSettingsPage::applySettings()
     {
         m_settings->reset("JoinServerOnLaunchAddress");
     }
+
+    // FIXME: This should probably be called by a signal instead
+    m_instance->updateRuntimeContext();
 }
 
 void InstanceSettingsPage::loadSettings()
diff --git a/libraries/systeminfo/include/sys.h b/libraries/systeminfo/include/sys.h
index bd6e2486a..6a6a7c82f 100644
--- a/libraries/systeminfo/include/sys.h
+++ b/libraries/systeminfo/include/sys.h
@@ -56,8 +56,4 @@ struct DistributionInfo
 DistributionInfo getDistributionInfo();
 
 uint64_t getSystemRam();
-
-bool isSystem64bit();
-
-bool isCPU64bit();
 }
diff --git a/libraries/systeminfo/src/sys_apple.cpp b/libraries/systeminfo/src/sys_apple.cpp
index 6353b747b..b6d62c1ae 100644
--- a/libraries/systeminfo/src/sys_apple.cpp
+++ b/libraries/systeminfo/src/sys_apple.cpp
@@ -55,18 +55,6 @@ uint64_t Sys::getSystemRam()
     }
 }
 
-bool Sys::isCPU64bit()
-{
-    // not even going to pretend I'm going to support anything else
-    return true;
-}
-
-bool Sys::isSystem64bit()
-{
-    // yep. maybe when we have 128bit CPUs on consumer devices.
-    return true;
-}
-
 Sys::DistributionInfo Sys::getDistributionInfo()
 {
     DistributionInfo result;
diff --git a/libraries/systeminfo/src/sys_unix.cpp b/libraries/systeminfo/src/sys_unix.cpp
index b30985226..3c63e73a4 100644
--- a/libraries/systeminfo/src/sys_unix.cpp
+++ b/libraries/systeminfo/src/sys_unix.cpp
@@ -82,17 +82,6 @@ uint64_t Sys::getSystemRam()
     return 0; // nothing found
 }
 
-bool Sys::isCPU64bit()
-{
-    return isSystem64bit();
-}
-
-bool Sys::isSystem64bit()
-{
-    // kernel build arch on linux
-    return QSysInfo::currentCpuArchitecture() == "x86_64";
-}
-
 Sys::DistributionInfo Sys::getDistributionInfo()
 {
     DistributionInfo systemd_info = read_os_release();
diff --git a/libraries/systeminfo/src/sys_win32.cpp b/libraries/systeminfo/src/sys_win32.cpp
index 430b87e47..5bf510cf8 100644
--- a/libraries/systeminfo/src/sys_win32.cpp
+++ b/libraries/systeminfo/src/sys_win32.cpp
@@ -27,28 +27,6 @@ uint64_t Sys::getSystemRam()
     return (uint64_t)status.ullTotalPhys;
 }
 
-bool Sys::isSystem64bit()
-{
-#if defined(_WIN64)
-    return true;
-#elif defined(_WIN32)
-    BOOL f64 = false;
-    return IsWow64Process(GetCurrentProcess(), &f64) && f64;
-#else
-    // it's some other kind of system...
-    return false;
-#endif
-}
-
-bool Sys::isCPU64bit()
-{
-    SYSTEM_INFO info;
-    ZeroMemory(&info, sizeof(SYSTEM_INFO));
-    GetNativeSystemInfo(&info);
-    auto arch = info.wProcessorArchitecture;
-    return arch == PROCESSOR_ARCHITECTURE_AMD64 || arch == PROCESSOR_ARCHITECTURE_IA64;
-}
-
 Sys::DistributionInfo Sys::getDistributionInfo()
 {
     DistributionInfo result;
diff --git a/tests/Library_test.cpp b/tests/Library_test.cpp
index 869c76735..db8380c7f 100644
--- a/tests/Library_test.cpp
+++ b/tests/Library_test.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include <QTest>
 
 #include <minecraft/MojangVersionFormat.h>
@@ -5,6 +40,7 @@
 #include <minecraft/Library.h>
 #include <net/HttpMetaCache.h>
 #include <FileSystem.h>
+#include <RuntimeContext.h>
 
 class LibraryTest : public QObject
 {
@@ -24,6 +60,14 @@ private:
     {
         return {FS::PathCombine(cache->getBasePath("libraries"), relative)};
     }
+
+    RuntimeContext dummyContext(QString system = "linux", QString arch = "64", QString realArch = "amd64") {
+        RuntimeContext r;
+        r.javaArchitecture = arch;
+        r.javaRealArchitecture = realArch;
+        r.system = system;
+        return r;
+    }
 private
 slots:
     void initTestCase()
@@ -34,12 +78,13 @@ slots:
     }
     void test_legacy()
     {
+        RuntimeContext r = dummyContext();
         Library test("test.package:testname:testversion");
         QCOMPARE(test.artifactPrefix(), QString("test.package:testname"));
         QCOMPARE(test.isNative(), false);
 
         QStringList jar, native, native32, native64;
-        test.getApplicableFiles(currentSystem, jar, native, native32, native64, QString());
+        test.getApplicableFiles(r, jar, native, native32, native64, QString());
         QCOMPARE(jar, getStorage("test/package/testname/testversion/testname-testversion.jar"));
         QCOMPARE(native, {});
         QCOMPARE(native32, {});
@@ -47,10 +92,11 @@ slots:
     }
     void test_legacy_url()
     {
+        RuntimeContext r = dummyContext();
         QStringList failedFiles;
         Library test("test.package:testname:testversion");
         test.setRepositoryURL("file://foo/bar");
-        auto downloads = test.getDownloads(currentSystem, cache.get(), failedFiles, QString());
+        auto downloads = test.getDownloads(r, cache.get(), failedFiles, QString());
         QCOMPARE(downloads.size(), 1);
         QCOMPARE(failedFiles, {});
         NetAction::Ptr dl = downloads[0];
@@ -58,27 +104,29 @@ slots:
     }
     void test_legacy_url_local_broken()
     {
+        RuntimeContext r = dummyContext();
         Library test("test.package:testname:testversion");
         QCOMPARE(test.isNative(), false);
         QStringList failedFiles;
         test.setHint("local");
-        auto downloads = test.getDownloads(currentSystem, cache.get(), failedFiles, QString());
+        auto downloads = test.getDownloads(r, cache.get(), failedFiles, QString());
         QCOMPARE(downloads.size(), 0);
         QCOMPARE(failedFiles, {"testname-testversion.jar"});
     }
     void test_legacy_url_local_override()
     {
+        RuntimeContext r = dummyContext();
         Library test("com.paulscode:codecwav:20101023");
         QCOMPARE(test.isNative(), false);
         QStringList failedFiles;
         test.setHint("local");
-        auto downloads = test.getDownloads(currentSystem, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
+        auto downloads = test.getDownloads(r, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
         QCOMPARE(downloads.size(), 0);
         qDebug() << failedFiles;
         QCOMPARE(failedFiles.size(), 0);
 
         QStringList jar, native, native32, native64;
-        test.getApplicableFiles(currentSystem, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
+        test.getApplicableFiles(r, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
         QCOMPARE(jar, {QFileInfo(QFINDTESTDATA("testdata/Library/codecwav-20101023.jar")).absoluteFilePath()});
         QCOMPARE(native, {});
         QCOMPARE(native32, {});
@@ -86,19 +134,20 @@ slots:
     }
     void test_legacy_native()
     {
+        RuntimeContext r = dummyContext();
         Library test("test.package:testname:testversion");
-        test.m_nativeClassifiers[OpSys::Os_Linux]="linux";
+        test.m_nativeClassifiers["linux"] = "linux";
         QCOMPARE(test.isNative(), true);
         test.setRepositoryURL("file://foo/bar");
         {
             QStringList jar, native, native32, native64;
-            test.getApplicableFiles(Os_Linux, jar, native, native32, native64, QString());
+            test.getApplicableFiles(r, jar, native, native32, native64, QString());
             QCOMPARE(jar, {});
             QCOMPARE(native, getStorage("test/package/testname/testversion/testname-testversion-linux.jar"));
             QCOMPARE(native32, {});
             QCOMPARE(native64, {});
             QStringList failedFiles;
-            auto dls = test.getDownloads(Os_Linux, cache.get(), failedFiles, QString());
+            auto dls = test.getDownloads(r, cache.get(), failedFiles, QString());
             QCOMPARE(dls.size(), 1);
             QCOMPARE(failedFiles, {});
             auto dl = dls[0];
@@ -107,49 +156,52 @@ slots:
     }
     void test_legacy_native_arch()
     {
+        RuntimeContext r = dummyContext();
         Library test("test.package:testname:testversion");
-        test.m_nativeClassifiers[OpSys::Os_Linux]="linux-${arch}";
-        test.m_nativeClassifiers[OpSys::Os_OSX]="osx-${arch}";
-        test.m_nativeClassifiers[OpSys::Os_Windows]="windows-${arch}";
+        test.m_nativeClassifiers["linux"]="linux-${arch}";
+        test.m_nativeClassifiers["osx"]="osx-${arch}";
+        test.m_nativeClassifiers["windows"]="windows-${arch}";
         QCOMPARE(test.isNative(), true);
         test.setRepositoryURL("file://foo/bar");
         {
             QStringList jar, native, native32, native64;
-            test.getApplicableFiles(Os_Linux, jar, native, native32, native64, QString());
+            test.getApplicableFiles(r, jar, native, native32, native64, QString());
             QCOMPARE(jar, {});
             QCOMPARE(native, {});
             QCOMPARE(native32, getStorage("test/package/testname/testversion/testname-testversion-linux-32.jar"));
             QCOMPARE(native64, getStorage("test/package/testname/testversion/testname-testversion-linux-64.jar"));
             QStringList failedFiles;
-            auto dls = test.getDownloads(Os_Linux, cache.get(), failedFiles, QString());
+            auto dls = test.getDownloads(r, cache.get(), failedFiles, QString());
             QCOMPARE(dls.size(), 2);
             QCOMPARE(failedFiles, {});
             QCOMPARE(dls[0]->m_url, QUrl("file://foo/bar/test/package/testname/testversion/testname-testversion-linux-32.jar"));
             QCOMPARE(dls[1]->m_url, QUrl("file://foo/bar/test/package/testname/testversion/testname-testversion-linux-64.jar"));
         }
+        r.system = "windows";
         {
             QStringList jar, native, native32, native64;
-            test.getApplicableFiles(Os_Windows, jar, native, native32, native64, QString());
+            test.getApplicableFiles(r, jar, native, native32, native64, QString());
             QCOMPARE(jar, {});
             QCOMPARE(native, {});
             QCOMPARE(native32, getStorage("test/package/testname/testversion/testname-testversion-windows-32.jar"));
             QCOMPARE(native64, getStorage("test/package/testname/testversion/testname-testversion-windows-64.jar"));
             QStringList failedFiles;
-            auto dls = test.getDownloads(Os_Windows, cache.get(), failedFiles, QString());
+            auto dls = test.getDownloads(r, cache.get(), failedFiles, QString());
             QCOMPARE(dls.size(), 2);
             QCOMPARE(failedFiles, {});
             QCOMPARE(dls[0]->m_url, QUrl("file://foo/bar/test/package/testname/testversion/testname-testversion-windows-32.jar"));
             QCOMPARE(dls[1]->m_url, QUrl("file://foo/bar/test/package/testname/testversion/testname-testversion-windows-64.jar"));
         }
+        r.system = "osx";
         {
             QStringList jar, native, native32, native64;
-            test.getApplicableFiles(Os_OSX, jar, native, native32, native64, QString());
+            test.getApplicableFiles(r, jar, native, native32, native64, QString());
             QCOMPARE(jar, {});
             QCOMPARE(native, {});
             QCOMPARE(native32, getStorage("test/package/testname/testversion/testname-testversion-osx-32.jar"));
             QCOMPARE(native64, getStorage("test/package/testname/testversion/testname-testversion-osx-64.jar"));
             QStringList failedFiles;
-            auto dls = test.getDownloads(Os_OSX, cache.get(), failedFiles, QString());
+            auto dls = test.getDownloads(r, cache.get(), failedFiles, QString());
             QCOMPARE(dls.size(), 2);
             QCOMPARE(failedFiles, {});
             QCOMPARE(dls[0]->m_url, QUrl("file://foo/bar/test/package/testname/testversion/testname-testversion-osx-32.jar"));
@@ -158,103 +210,112 @@ slots:
     }
     void test_legacy_native_arch_local_override()
     {
+        RuntimeContext r = dummyContext();
         Library test("test.package:testname:testversion");
-        test.m_nativeClassifiers[OpSys::Os_Linux]="linux-${arch}";
+        test.m_nativeClassifiers["linux"]="linux-${arch}";
         test.setHint("local");
         QCOMPARE(test.isNative(), true);
         test.setRepositoryURL("file://foo/bar");
         {
             QStringList jar, native, native32, native64;
-            test.getApplicableFiles(Os_Linux, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
+            test.getApplicableFiles(r, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
             QCOMPARE(jar, {});
             QCOMPARE(native, {});
             QCOMPARE(native32, {QFileInfo(QFINDTESTDATA("testdata/Library/testname-testversion-linux-32.jar")).absoluteFilePath()});
             QCOMPARE(native64, {QFileInfo(QFINDTESTDATA("testdata/Library") + "/testname-testversion-linux-64.jar").absoluteFilePath()});
             QStringList failedFiles;
-            auto dls = test.getDownloads(Os_Linux, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
+            auto dls = test.getDownloads(r, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
             QCOMPARE(dls.size(), 0);
             QCOMPARE(failedFiles, {QFileInfo(QFINDTESTDATA("testdata/Library") + "/testname-testversion-linux-64.jar").absoluteFilePath()});
         }
     }
     void test_onenine()
     {
+        RuntimeContext r = dummyContext("osx");
         auto test = readMojangJson(QFINDTESTDATA("testdata/Library/lib-simple.json"));
         {
             QStringList jar, native, native32, native64;
-            test->getApplicableFiles(Os_OSX, jar, native, native32, native64, QString());
+            test->getApplicableFiles(r, jar, native, native32, native64, QString());
             QCOMPARE(jar, getStorage("com/paulscode/codecwav/20101023/codecwav-20101023.jar"));
             QCOMPARE(native, {});
             QCOMPARE(native32, {});
             QCOMPARE(native64, {});
         }
+        r.system = "linux";
         {
             QStringList failedFiles;
-            auto dls = test->getDownloads(Os_Linux, cache.get(), failedFiles, QString());
+            auto dls = test->getDownloads(r, cache.get(), failedFiles, QString());
             QCOMPARE(dls.size(), 1);
             QCOMPARE(failedFiles, {});
             QCOMPARE(dls[0]->m_url, QUrl("https://libraries.minecraft.net/com/paulscode/codecwav/20101023/codecwav-20101023.jar"));
         }
+        r.system = "osx";
         test->setHint("local");
         {
             QStringList jar, native, native32, native64;
-            test->getApplicableFiles(Os_OSX, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
+            test->getApplicableFiles(r, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
             QCOMPARE(jar, {QFileInfo(QFINDTESTDATA("testdata/Library/codecwav-20101023.jar")).absoluteFilePath()});
             QCOMPARE(native, {});
             QCOMPARE(native32, {});
             QCOMPARE(native64, {});
         }
+        r.system = "linux";
         {
             QStringList failedFiles;
-            auto dls = test->getDownloads(Os_Linux, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
+            auto dls = test->getDownloads(r, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
             QCOMPARE(dls.size(), 0);
             QCOMPARE(failedFiles, {});
         }
     }
     void test_onenine_local_override()
     {
+        RuntimeContext r = dummyContext("osx");
         auto test = readMojangJson(QFINDTESTDATA("testdata/Library/lib-simple.json"));
         test->setHint("local");
         {
             QStringList jar, native, native32, native64;
-            test->getApplicableFiles(Os_OSX, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
+            test->getApplicableFiles(r, jar, native, native32, native64, QFINDTESTDATA("testdata/Library"));
             QCOMPARE(jar, {QFileInfo(QFINDTESTDATA("testdata/Library/codecwav-20101023.jar")).absoluteFilePath()});
             QCOMPARE(native, {});
             QCOMPARE(native32, {});
             QCOMPARE(native64, {});
         }
+        r.system = "linux";
         {
             QStringList failedFiles;
-            auto dls = test->getDownloads(Os_Linux, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
+            auto dls = test->getDownloads(r, cache.get(), failedFiles, QFINDTESTDATA("testdata/Library"));
             QCOMPARE(dls.size(), 0);
             QCOMPARE(failedFiles, {});
         }
     }
     void test_onenine_native()
     {
+        RuntimeContext r = dummyContext("osx");
         auto test = readMojangJson(QFINDTESTDATA("testdata/Library/lib-native.json"));
         QStringList jar, native, native32, native64;
-        test->getApplicableFiles(Os_OSX, jar, native, native32, native64, QString());
+        test->getApplicableFiles(r, jar, native, native32, native64, QString());
         QCOMPARE(jar, QStringList());
         QCOMPARE(native, getStorage("org/lwjgl/lwjgl/lwjgl-platform/2.9.4-nightly-20150209/lwjgl-platform-2.9.4-nightly-20150209-natives-osx.jar"));
         QCOMPARE(native32, {});
         QCOMPARE(native64, {});
         QStringList failedFiles;
-        auto dls = test->getDownloads(Os_OSX, cache.get(), failedFiles, QString());
+        auto dls = test->getDownloads(r, cache.get(), failedFiles, QString());
         QCOMPARE(dls.size(), 1);
         QCOMPARE(failedFiles, {});
         QCOMPARE(dls[0]->m_url, QUrl("https://libraries.minecraft.net/org/lwjgl/lwjgl/lwjgl-platform/2.9.4-nightly-20150209/lwjgl-platform-2.9.4-nightly-20150209-natives-osx.jar"));
     }
     void test_onenine_native_arch()
     {
+        RuntimeContext r = dummyContext("windows");
         auto test = readMojangJson(QFINDTESTDATA("testdata/Library/lib-native-arch.json"));
         QStringList jar, native, native32, native64;
-        test->getApplicableFiles(Os_Windows, jar, native, native32, native64, QString());
+        test->getApplicableFiles(r, jar, native, native32, native64, QString());
         QCOMPARE(jar, {});
         QCOMPARE(native, {});
         QCOMPARE(native32, getStorage("tv/twitch/twitch-platform/5.16/twitch-platform-5.16-natives-windows-32.jar"));
         QCOMPARE(native64, getStorage("tv/twitch/twitch-platform/5.16/twitch-platform-5.16-natives-windows-64.jar"));
         QStringList failedFiles;
-        auto dls = test->getDownloads(Os_Windows, cache.get(), failedFiles, QString());
+        auto dls = test->getDownloads(r, cache.get(), failedFiles, QString());
         QCOMPARE(dls.size(), 2);
         QCOMPARE(failedFiles, {});
         QCOMPARE(dls[0]->m_url, QUrl("https://libraries.minecraft.net/tv/twitch/twitch-platform/5.16/twitch-platform-5.16-natives-windows-32.jar"));