The minimum requirements for Apple devices are:
iPad 3 and higher or iPhone 5 and higher
More than 2.5 GB free memory space (3GB recommended)
Although these are the minimum requirements, it is not set in stone. There are devices that meet the minimum but can't run the game and there are also some devices that don't meet the minimum that can run the game. We can only advise you to go the app store for your device, and if it can't run the game, your store will inform you that it's not compatible.
If your store lets you download it, but it doesn't run well on your device, then you can request a refund, If you're on an iOS device, Apple refunds at their discretion.