From what you say it looks like the app is still supported but it was removed from the Store only. Maybe it was because of "Hangouts" in its name, I heard they were about to remove apps from the Store which have a name it something else in itself. For example the developer of Windows Novosti (an app for Windows fans from former Yugoslav republics) has renamed his app to WinNovosti not to have this "Windows".
Just ask them, and let us know what they said. 
Unfortunately it has gotten really slow and also notifications, the most important thing in my opinion wasn't reliably working.
I emailed them earlier this week (dec 6) because I have lots of problem with notifications stop working.
I uninstalled it because it was getting really unreliable only to find I couldn't install it again.
They said they were having problems with windows store
Man I thought I was the only one that used it
On a positive note though, the number of random reboots I was having were drastically reduced once I installed the release preview. I am still experiencing random reboots, just not several times per day as was happening with the current production build.
Unfortunately, I've been having problems with the app for quite a while now. In mid September, they came out with 1.0.47 or something and was a lot more feature packed I guess but since then, it hasn't been really reliable for me in terms of being notified and I find it slow.
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