on the branch release/CalendarServer-9.1 I have run the podA & podB server setup and tested the migration of user01 from podA to podB. Before migrating, I share user01's calendar to user02. After the migration, I observe that the shared calendar is partly broken: user02 on podA still views the calendar as shared from user01, but user01 seems to have lost the shared-owner information about this calendar. I think I might have figured out the problem: The 'shared' value in the message column in the calendar_bind table is not copied from podA to podB during user01 migration, which is confirmed by the shared-owner information being migrated if the attached modification is done.