Gmail on Android and Hangouts for Android updated: here is what may interest you.

No innovative functionality from one side to another. But we can observe that, henceforth Gmail on Android brings cleaner design for its conversation view, includes checkmarks for multiple message selection: this means you can easily see

what messages you are about to move, archive or delete. In addition the app will now tell you, right in your inbox, if account sync is off.

Regarding the new version of Hangouts for Android, henceforth, you can see who's reachable right now on Hangouts: Green icons mean they are, and gray icons mean they aren't.

Finally, from top to bottom you'll now see 'People you Hangout with’, 'Suggested People', and 'Other Contacts'.