I've a 1520. Yesterday's install from the WPC article link worked for me yesterday and this AM.
That version is now gone from public search on the Store.
I got the email invite today and followed that link. It shows an update with today's date, but my phone wouldn't update. Looking inside tha (still functioning) app installed yesterday showed a version number of 2.x.x or some such. Looking at the version number of the app from the invite email of today shows a version 0.9.0.1
Thinking the "leaked" link of yesterday's article is not as official as today's Beta Test invite... I uninstalled Opera Mini and reinstalled from the Beta Test invite email link.
Now Opera Mini crashes on boot.
Here's the link:
Opera Mini - beta | Windows Phone Apps+Games Store (United States)
Under App requires, note that HD1080p is missing...