CODEWITHSUNDEEP
outlookoffice365imap
Andrew Daviel
Andrew Daviel

Reputation: 29

How can I preserve IMAP flags (Forwarded, user flags) when migrating to Office 365 ?

We have a heterogeneous collection of mail clients (Thunderbird, Apple Mail, Squirrelmail, Outlook etc.) on different platforms (Linux, Mac, Windows, Android) using a UW IMAP server, which supports FLAGS and PERMANENTFLAGS. Thunderbird uses them for junk control, all clients use $Forwarded, and many users use them for mail management (tagging messages with categories such as "Important", or colouring them.

We are trying to migrate to Office365. As far as I can tell, the Office365 IMAP server does not support PERMANENTFLAGS at all, but the Web interface and Outlook client do support "Categories", which from a user perspective are the same thing (they could tag their message "Important" and colour it red).

Are there any tools which would perform this migration, perhaps using MAPI or EWS on the Office365 side ?

Also, I have been getting inconsistent results migrating just the legacy IMAP flags (Answered, Flagged) which Office365 does support - often if I copy folders with IMAP the flags are visible with an IMAP client, while if I copy folders with Outlook or the Office365 batch migration tool, the flags are visible with Outlook or the Office365 web portal. Are there any reliable migration tools which will set flags properly ?

Upvotes: 0

Views: 1475

Answers (1)

Andrew Daviel
Andrew Daviel

Reputation: 29

Regarding migration of standard legacy flags, I found a recipe using two passes of the open-source tool imapsync - one pass to sync mailboxes without flags, and a second pass to set the flags.

For conversion of user flags, I modified an existing tool "mixfix" I had written to repair UW MIX format mailboxes. The script adds X- mail headers for each user flag, so that a message might have X-Flag-Important: True. In Outlook, I can write a rule to set an email category based on a message header, and so by downloading and running a ruleset on a given folder, finally migrate Thunderbird tags to Outlook categories. It must be run on a desktop Outlook client, though - the rules will not run on the server.

Upvotes: 1

Related Questions