Unable to play game without updating. No update available on IOS

I'm currently playing the game on the latest IOS IPhone 7 Plus my game has been working fine but yesterday I had a pop up for an update when I clicked on the update it opened my app store however there was no update. Now I'm unable to play the game as it tells me (More fun awaits! It's time to update for more fun!) With a large green button saying Update. However there is no update available in the app store. I'm unable to open the game until it's updated but again I stress there is no update in app store and where the update button usually is. it just says open. This is quite frustrating especially as the game is played in real time hours I feel like I'm losing out on earnings within the game.