The Stores may show that a new update is available but the version may still be unpublished. Here is a very important notice!

'Updates are released by the Stores (Google Play Market, App Store)'

Depending on the country and the Store of the device, some players may receive the updates a bit later than others (App Store is usually the last one to publish).
Just make sure to enable 'automatic updates' from the Settings to receive the updates automatically and don't miss out on new versions of the game.