MoodBar has been removed from the Wikimedia wikis. 
The live option for the Tipsy notice tool has been removed. Gadgets and user scripts which use it need to be updated. 
Editors who use Firefox 50 might get logged out or fail to save their edits. This is because of a browser bug. Until this is fixed you can enter about:config in the address bar and set network.cookie.maxPerHost to 5000. Firefox 50 is the current version of the Firefox.