From the little information you have, its hard to tell if its a message from the Play Store or the app itself has a little "call home" feature to check you are on the latest version. I would try going into Airplane mode (ie turn all network access off, and make sure the app is not already running) and see if the message still pops-up. If it still does, then the app may have an internal countdown type of thingy to ensure you update it. A lot more investigation would be needed to nail it down, or you could get lucky. If its a "call home", check the adaway thread (https://forum.xda-developers.com/sho....php?t=2190753) for DNS logging to find a possible host you could block to circumvent the "call-home" check. Search the web by app name and problem, someone else may already have a solution.