--- a/js/xpconnect/loader/mozJSSubScriptLoader.cpp
+++ b/js/xpconnect/loader/mozJSSubScriptLoader.cpp
@@ -124,17 +124,18 @@ PrepareScript(nsIURI* uri,
               const nsAString& charset,
               const char* buf,
               int64_t len,
               bool reuseGlobal,
               MutableHandleScript script,
               MutableHandleFunction function)
 {
     JS::CompileOptions options(cx);
-    options.setFileAndLine(uriStr, 1);
+    options.setFileAndLine(uriStr, 1)
+           .setVersion(JSVERSION_LATEST);
     if (!charset.IsVoid()) {
         char16_t* scriptBuf = nullptr;
         size_t scriptLength = 0;
 
         nsresult rv =
             nsScriptLoader::ConvertToUTF16(nullptr, reinterpret_cast<const uint8_t*>(buf), len,
                                            charset, nullptr, scriptBuf, scriptLength);