Was that last update before or after the trouble began?
This sort of thing is an example of why I do not allow ANY appstore to autoupdate.
(Not trying to sound 'preachy', unless of course you work for Google. If that is the case....oh, nevermind.)
First, it can be difficult (thanks, Google!) to set stock apps back to older versions.
The way I go about it seems to work, but it does take some steps and it is usually something that takes a few minutes.
First, it would be of great help if you could positively identify exactly which app is causing the grief.
Then I need to know when the issue began.
At that point I would have you download and install a secondary appstore called UpToDown.
This appstore allows for the downloading of older versions of apps.
But before we get into all of that, let's begin with what is simple.
Go into Google PlayStore, and turn off autoupdate.
If what I think happened is the cause, then if we fix it then Google will just screw it right back up- of course they will wait until around 2AM to do it.
I am not familiar with the 'announcement' thing you speak of.
Are you using the stock (built in) alarm app, or have you downloaded a different one and are using that?
If it is a third party app (one that you downloaded) then this will be a bit easier.
If you are using a stock alarm app that got updated and then caused this trouble, we can deal with that with some extra effort.