Apparently currently the only option to "opt out" of this upgrade is to have your current account deleted and playlists etc. transferred to a new account. It's an account level "feature". See recent posts in the thread I linked.
Thanks, I just voted. This just started when I joined the family plan and sent an invitation to join. After she joined, her player version changed. She can log into my account and the full version player comes back. So right now I'm paying for the family plan with limited features on one member. It's crazy.
I have this issue as well and it doesn't seem like it will change anytime soon.
I did some digging and it seems like they are performing testing with various users where we are switched to the web app version from the native desktop app (edit: or switched from an old desktop client to the new version).
This means we no longer have access to features like sorting or multi-select, which I find infuriating because I use both of these multiple times a day. This is a big reason why I'm paying for premium - music libraray management. I feel like it's only fair to allow us to switch back if this is being forced upon paying customers.
It seems like this is intentional from Spotify and not everyone is experiencing it. Hope this helps.
This problem occurs only for those who auto updated to the latest version of Spotify. If you haven't updated to the latest one then you're fine. That's why the solution is to downgrade back to the older version if you want the sorting feature back. Cheers!