Migration from cyrus 3.4.3 to 3.6.0~bet a2-1 failed

Hello,
Using debian bookworm, the cyrus-imapd was updated from 3.4.3 to 3.6.0~beta2-1 this Friday. There was no warning about any migration or post check to perform before applying the updated packages.
The update procedure didn't went well but I didn't realized it.
process type:START name:recover path:/usr/sbin/cyrus age:0.000s pid:678146 signaled to death by signal 11 (Segmentation fault)

I restarted cyrus via systemctl and saw that I couldn't access to mail,
despite the fact that all the mails are still in the usual (legacy?) /var/spool/cyrus/mail/f/fuser.
I also saw that a new user was created under uuid folder and this user is receiving my new mails.
I tried to downgrade to previous version but cyrus couldn't find my legacy user's mailbox.
I reinstalled the beta2 and checked on your website. I tried to perfrom the relocate_by_id command but I could not find it in any debian packages.

I copied all mails from my /var/spool/cyrus/mail/f/fuser to the uuid folder and performed several reconstruct commands.

I managed to get my mails back under the user with uuid but all the sublfolders failed to reconstruct (segmentation fault)

cyrus/reconstruct[54080]: IOERROR: lock failed: mailbox=<user.fuser.myfolder> error=<Invalid mailbox name> syserror=<No such file or directory> func=<mailbox_open_advanced>

and, yes, fuser.myfolder exists under /var/spool/cyrus/mail/uuid/

Could you help me recover my subfolders and I suppose my sieve, addresbooks and calendars?
I still have the backup of /var/spool/cyrus and /var/spool/sieve I have made after the restart due to initial segmentation fault (which means update process was started)

Thank you so much in advance for your help.

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