Updated Mixin to 0.6.4-SNAPSHOT and set mixin target level

build.gradle

@@ -61,7 +61,7 @@ configurations {
 dependencies {
     compile 'org.projectlombok:lombok:1.16.4'
 
-    compile 'org.spongepowered:mixin:0.4.3'
+    compile 'org.spongepowered:mixin:0.6.4-SNAPSHOT'
     shade 'com.googlecode.mp4parser:isoparser:1.1.7'
     shade 'org.apache.commons:commons-exec:1.3'
     shade 'com.google.apis:google-api-services-youtube:v3-rev178-1.22.0'

src/main/resources/mixins.compat.shaders.replaymod.json

@@ -8,5 +8,6 @@
     "MixinShaderRenderChunk",
     "MixinShaderRenderGlobal"
   ],
+  "compatibilityLevel": "JAVA_8",
   "refmap": "mixins.replaymod.refmap.json"
 }

src/main/resources/mixins.recording.replaymod.json

@@ -9,5 +9,6 @@
     "MixinNetworkDispatcher",
     "MixinRenderGlobal"
   ],
+  "compatibilityLevel": "JAVA_8",
   "refmap": "mixins.replaymod.refmap.json"
 }

src/main/resources/mixins.render.replaymod.json

@@ -11,5 +11,6 @@
   ],
   "server": [],
   "client": [],
+  "compatibilityLevel": "JAVA_8",
   "refmap": "mixins.replaymod.refmap.json"
 }

src/main/resources/mixins.replay.replaymod.json

@@ -15,5 +15,6 @@
   ],
   "server": [],
   "client": [],
+  "compatibilityLevel": "JAVA_8",
   "refmap": "mixins.replaymod.refmap.json"
 }