can we still use beta profile to avoid update nag?

I'd previously been using a tvOS beta profile on my iphone/ipad to avoid the daily update nag until a later point release made things bearable. Is this still possible? It seems most articles on the procedure are old and have dead links to installing these profiles.

Would especially like it to put on my mom's 5s/mini2 that would likely be brutal on iOS 11.

 

Thankyou!!!