Quotaroot and xfer

[Marco]

Hello,

  I'm trying xfer from 2.4.20 to 3.0.7. It seems that xfer denies the 
operation when the destination server finds a mailbox with no quota.

The xfer on source server says "The remote Server(s) denied the operation".

The destination cyrus-3.0.7 server logs say:

Aug  1 10:16:09 cyrus-3.0.7 cyrus/imap[9972]: LOSTQUOTA: unable to 
record change of 85789593 bytes and 7635 messages in quota 
example.com!user.utente^archivio.Posta archiviata: Quota root does not exist

This is right. The above mailbox is a quotaroot with no quota limit.
After that message I only see delete operations:

Aug  1 10:16:09 cyrus-3.0.7 cyrus/imap[9972]: Deleted mailbox 
example.com!user.utente^archivio[...]


Maybe, is quota limit a requisite to run xfer?

Thank you very much for the help
Marco