If you can not update Pethereum on an Apple device;
If you are using IOS 13:
Open your App Store profile from the App Store and swipe down to see the update button at the bottom of the screen next to Pethereum.
If you are using any other version of IOS:
Open the App Store application on your device and tap on the Updates menu button at the bottom of the screen.
Swipe down a few times from the top of the Updates page to refresh it.
Check the update list and find Pethereum and tap the Update button next to it.
When you refresh the update page, you will be able to update Pethereum.
If you can not update Pethereum from Google Play Store;
Please clean the Google Play Store’s cache files from Settings>Applications>Google Play Store>Storage & Cache and press the Clear Cache button.
Warning: This option will remove your Google Play Store’s cache files, which will force Google Play Store to reload all game pages. Also, this option will clean your Google Play Store search history.