It seems as though PlayStation Mobile is as good as done, with Sony conceding and dropping support for PSM games on PlayStation-certified Android devices.
“There is the possibility that content may not work correctly with devices that have been updated to Android ™ OS version 4.4.3 or later” says the translated post on Sony’s Japanese site. It also looks like, going by their FAQ, that you won’t be able to download content or access the PS Mobile store on certain devices.
So, if you don’t update your Android device, then you’ll still be able to access the entire library of games, but updating brings a risk with compatibility issues. It’s a bit unfair, but Sony say that their focus is on content for PS Vita TV and PS Vita from now on, and that PSM will continue.