how to teams scrim after updates?

from my understanding, tournaments are usually played on an older patch if a new one comes out right before it/during it so I'm assuming the teams are also forced to scrim on those patches. can they only scrim with other teams in the tournament or do other teams (that are not part of the masters/champs) also get to choose what patch they play on?

Val pros have access to a Tournament Client that they use for all official matches. Im pretty sure it stays at whatever patch they are using in pro play. So pros can prac on that if need be.

Update will not come until after masters Shanghai, but before split 2, so nobody is affected by different patches.