If you are an existing Simple Control 4 or 5 user, you can upgrade to the Roomie Remote 6.5 app. Simply leave your older app installed on your iOS device and purchase the Roomie Remote 6.5 app on the same device. The base app is a paid upgrade, but any existing Simple Service purchased via Simple Control 5 is compatible as your subscription.
Your old configuration will be copied over to the new app automatically and upgraded one time when you install V6. The original configuration is not touched so if you were to return to the old app, you will see your old configuration and changes made in V6 will not be reflected in an older app.
If you have an existing Simple Service you can follow the instructions for transferring your Simple Service to Roomie Remote 6. The key is to use the Restore Purchases button in the old app to reflect your subscription in V6. This must be performed each time your subscription renews until you move your subscription to V6.
Please note: Roomie Remote 6.5 requires iOS 13.4 or later. The minimum iOS version is increased by one major every year. So the expected minimum in August 2021 will be iOS 14.X.