We are ready to change our Coexistence mode to Teams Only. If I change the mode for our organization, will the Skype Meetings automatically migrate to Teams meetings? If I set a single user to Teams Only mode I have the option to migrate the meetings:
I don't see the option if I change the whole organization.
Meetings will be updated when you set the whole organisation to Teams Only. Meeting Migration Service will upgrade the meetings as default, so actually you don't have the option to not migrate meetings when changing for the whole org.
See section ‘Updating meetings when assigning TeamsUpgradePolicy’
Meeting migration is only invoked when you grant TeamsUpgradePolicy for a specific user. If you grant TeamsUpgradePolicy with mode=TeamsOnly or mode=SfBWithTeamsCollabAndMeetings on a tenant-wide basis, meeting migration is not invoked