Just upgraded to Nougat - Textra notifications disappearing from tray So I LOVE the Textra app, but after I just upgraded to Nougat on my OnePlus 3T - I noticed that my text message notifications disappear form the notification tray on my main screen after a while. It used to be that they would stay in the notification bar until I accessed/dismissed them and then they'd disappear. 

Now I get a message and it temporarily shows the Textra notification icon in the tray at the top of the main screen, but if I lock the phone without answering and then unlock again the notification disappears. 

This is inconvenient because after a few hours away from my phone, I have no indication that I got any texts unless I remember to open up the textra app and see what's new. I liked it better before!

I couldn't figure out where to ask Textra directly - so I came here! Thanks.
I had the same problem. The Textra app includes a support section (settings > support) and this is one of the top topics. Here is the text.

OnePlus running Android 7 - Notification disappears / goes away

To fix, do Android Settings > Battery > Aggressive doze and app hibernation (dotdotdot top right) > set Textra to 'Not optimized'.