From the Tidal website
HOW WILL THESE CHANGES IMPACT MY COLLECTION?
MQA:
If you have an MQA track or album in your Collection – including in playlists – the track will automatically be replaced by the highest quality FLAC version that has been distributed to TIDAL.
If you have an MQA track or album downloaded for offline access, you will need to update to the latest version of the app on July 24. You will then be prompted to redownload these tracks. This will download the replacement FLAC version of any MQA track you previously downloaded.
360 Reality Audio:
If you have a 360 Reality Audio track or album in your Collection – including in a playlist or downloaded for offline access – you will see the track or album grayed out and unavailable for streaming if you try to select it.