The mobile versions of Pokemon HOME offered everyone a warning on April 14, 2021. Depending on your platform, you might lose access in a few months. A Pokemon HOME June 2021 update is on the way and when it appears, support for some Android and iOS firmware versions and iPhone models will be gone.
People with iOS devices are the ones who will be hit hardest by this Pokemon HOME update and lack of support. Both the iPhone 5s and iPhone 6, regardless of firmware, will be unable to play the game after the patch is released. If you have other phones or tablets and they still run iOS 9, iOS 10, or iOS 11, they also won’t work with the application. Anything after iOS 12 will be fine.
As for people with Android phones and tablets, they shouldn’t experience any issues. Android firmware 5.0 won’t be supported. However, everything after that will be fine. For reference, that firmware launched in 2014 and the current version available is Android 11. (If you’ve updated your phone since September 2020, this is likely what it is using.)
Pokemon HOME is available for the Nintendo Switch and mobile devices. The Pokemon HOME June 2021 update is on the way.