Going from 23.1.5. to 1.1? Or do you mean 23.2.1.?

But doesn't matter, always use the latest version from the respective app store. It does support both 23.2 and 23.1.

You should always try and be on the latest available version that exist on the app store. As Aleander Heinze mention, The apps in the app store is backwards compatible and we only do have one released app for all cloud versions, 

I also think you should download the apps prior to any upgrade of the IFS Cloud release on the server side. Then you will alwyas be sure it will work when you upgrade the IFS cloud server parts