You can’t roll back to a previous software version.

It’s not the update, otherwise you’d see thousands of posts.  We get about a half dozen of these after every update because the rebooting that occurs uncovers network problems. Specifically duplicate IP addresses. These will cause sporadic connections, disappearing components, etc. To solve, reboot/power cycle each of these in order:

Modem
Router
Hubs or switches
Wired Sonos components
Wireless Sonos components
Computers, printers
Phones, tablets, all other wireless devices

Note you can prevent duplicate IP addresses by reserving a permanent IP for each Sonos unit in your router setup. See your router manual for details.

Are you sure ?  Did you find it strange that sonos is rolling out version 14.20.1 already within  2 weeks releasing version 14.20? 
Maybe you guys have no problem with fixed ip numbers but i don’t use that with devices like sonos .

I'm 1000% sure.  The threads for actual update problems hit hundreds of pages.  It's been a week and you are the only one complaining.  Plus, I've been at this over a decade and I can count on one hand the number times the above procedure failed to fix a supposed "update problem".  It ain't the update, aside from the fact the update uncovers an underlying network problem.

You were right i had an issue with a network switch. After replacing the switch everything work well again