Some users got a warning about Wikipedia's security certificate last week. This was because of a problem GlobalSign had. This has now been fixed. Only a small number of users got the warning. 
Editors couldn't edit semi-protected pages in the Wikipedia app for Android. This has now been fixed in the beta version. 
Changes this week
There will be no new MediaWiki version this week. 
The Editing Department are working on a new wikitext editor. It will have tools that are in the visual editor but not in the wikitext editor today. You can read more about this. This is an early plan and things can change. The old wikitext editor will still exist.