If you wish to install a company iPad near the entrance of your office and use the Tapinout app it is best to have a more recent version.
If you purchase a very old version, you may not be able to download current versions of iOS which could cause slowness and issues.
If you go to the Apple app store and look for the Tapinout app you should find the oldest possible iOS version you can use. We recommend buying one that is at least 2 versions ahead in case further versions become unsupported.
📌Note: Currently, iPad is the only tablet that is supported as it is capable of using the mobile versions of apps and the app is not compatible with tablet devices.