diff -uNr 0ad-0.0.21-alpha.orig/source/scriptinterface/ScriptTypes.h 0ad-0.0.21-alpha/source/scriptinterface/ScriptTypes.h
--- 0ad-0.0.21-alpha.orig/source/scriptinterface/ScriptTypes.h	2016-09-02 18:19:31.000000000 +0200
+++ 0ad-0.0.21-alpha/source/scriptinterface/ScriptTypes.h	2016-11-09 07:14:16.227277422 +0100
@@ -79,19 +79,6 @@
 include paths.
 #endif
 
-#if MOZJS_MINOR_VERSION != 3
-#error Your compiler is trying to use an untested minor version of the \
-SpiderMonkey library. If you are a package maintainer, please make sure \
-to check very carefully that this version does not change the behaviour \
-of the code executed by SpiderMonkey. Different parts of the game (e.g. \
-the multiplayer mode) rely on deterministic behaviour of the JavaScript \
-engine. A simple way for testing this would be playing a network game \
-with one player using the old version and one player using the new \
-version. Another way for testing is running replays and comparing the \
-final hash (check trac.wildfiregames.com/wiki/Debugging#Replaymode). \
-For more information check this link: trac.wildfiregames.com/wiki/Debugging#Outofsync
-#endif
-
 class ScriptInterface;
 
 #endif // INCLUDED_SCRIPTTYPES
diff -uNr 0ad-0.0.21-alpha.orig/source/simulation2/serialization/BinarySerializer.cpp 0ad-0.0.21-alpha/source/simulation2/serialization/BinarySerializer.cpp
--- 0ad-0.0.21-alpha.orig/source/simulation2/serialization/BinarySerializer.cpp	2016-09-18 11:34:45.000000000 +0200
+++ 0ad-0.0.21-alpha/source/simulation2/serialization/BinarySerializer.cpp	2016-11-09 07:29:10.293824242 +0100
@@ -145,11 +145,7 @@
 			const JSClass* jsclass = JS_GetClass(obj);
 			if (!jsclass)
 				throw PSERROR_Serialize_ScriptError("JS_GetClass failed");
-// TODO: Remove this workaround for upstream API breakage when updating SpiderMonkey
-// See https://bugzilla.mozilla.org/show_bug.cgi?id=1236373
-#define JSCLASS_CACHED_PROTO_WIDTH js::JSCLASS_CACHED_PROTO_WIDTH
 			JSProtoKey protokey = JSCLASS_CACHED_PROTO_KEY(jsclass);
-#undef JSCLASS_CACHED_PROTO_WIDTH
 
 			if (protokey == JSProto_Object)
 			{