Merge remote-tracking branch 'origin/master' into squadcast-notification-support

# Conflicts:
#	src/languages/en.js

src/languages/en.js

@@ -582,5 +582,6 @@ export default {
     goAlert: "GoAlert",
     backupOutdatedWarning: "Deprecated: Since a lot of features added and this backup feature is a bit unmaintained, it cannot generate or restore a complete backup.",
     backupRecommend: "Please backup the volume or the data folder (./data/) directly instead.",
+    "Optional": "Optional",
     squadcast: "Squadcast",
 };