diff --git a/chrome/content/zotero/xpcom/data/dataObject.js b/chrome/content/zotero/xpcom/data/dataObject.js
index 795047db5..bbc72f034 100644
--- a/chrome/content/zotero/xpcom/data/dataObject.js
+++ b/chrome/content/zotero/xpcom/data/dataObject.js
@@ -1252,12 +1252,16 @@ Zotero.DataObject.prototype._finalizeErase = Zotero.Promise.coroutine(function*
 Zotero.DataObject.prototype.toResponseJSON = function (options) {
 	// TODO: library block?
 	
-	return {
+	var json = {
 		key: this.key,
 		version: this.version,
 		meta: {},
 		data: this.toJSON(options)
 	};
+	if (options.version) {
+		json.version = json.data.version = options.version;
+	}
+	return json;
 }
 
 
diff --git a/test/tests/syncEngineTest.js b/test/tests/syncEngineTest.js
index 720be9b58..ff5df058c 100644
--- a/test/tests/syncEngineTest.js
+++ b/test/tests/syncEngineTest.js
@@ -782,9 +782,9 @@ describe("Zotero.Sync.Data.Engine", function () {
 						},
 						JSON.stringify({
 							successful: {
-								"0": item2.toResponseJSON(),
-								"1": item1.toResponseJSON(),
-								"2": item3.toResponseJSON()
+								"0": item2.toResponseJSON({ version: lastLibraryVersion }),
+								"1": item1.toResponseJSON({ version: lastLibraryVersion }),
+								"2": item3.toResponseJSON({ version: lastLibraryVersion })
 							},
 							unchanged: {},
 							failed: {}