iRedMail — moving from zimbra to iredmail

Re: moving from zimbra to iredmail

null@example.com (ZhangHuangbin) — Fri, 20 Feb 2026 15:12:39 +0000

Another alternative is Dovecot imapc.
FYI https://doc.dovecot.org/2.3/admin_manua … mailboxes/

Re: moving from zimbra to iredmail

null@example.com (ZhangHuangbin) — Fri, 20 Feb 2026 15:05:11 +0000

If you use "imapsync" to migrate mailboxes, IMAP server on new server will generate new IMAP UIDs for all emails, but MUA doesn't have those new IMAP UIDs locally, so they're all considered as new emails and re-downloaded.

If your Zimbra uses Maildir format mailbox, you may consider migrating mailboxes with "rsync" directly, it copies all files inside user's mailbox, including IMAP flags and UIDs.

moving from zimbra to iredmail

null@example.com (openedgarage) — Fri, 20 Feb 2026 09:35:25 +0000

Hello,
I am in the process of moving data from zimbra to iredmail.
i am using imapsync for copying data something like:

/usr/bin/imapsync --host1 ... --delete2 --notls1 --port1 143 --port2 143 --notls2 --buffersize 8192 --nosyncacls --subscribe --search "SINCE 1-Jan-2017" --tmpdir /var/mail-migration --logdir /var/mail-migration --useheader "Message-Id" --usecache --syncinternaldates --noresyncflags

data is being copied correctly but now that i want to migrate ussers by just changing the mail server ip in outlook from zimbra to iredmail emails are being resynchornized. goal is to have them sync'ed up and not redownload everything. am i missing any flag in imapsync to do that? The thing is mailboxes are big anad will rquire a lot of time ot download again which is an issue for the user experience.