Metadata that is not saved by OfflineImap

Sebastian Spaeth Sebastian at
Tue Oct 25 15:51:22 BST 2011

On Sat, 15 Oct 2011 18:16:04 -0700, "abcdzywx at" wrote:

> account I have that is going to expire.  I would like to preserve all
> messages and metadata.  I would like to find out and verify what IMAP
> metadata OfflineIMAP does NOT save in the migration to the Maildir.
> 1) One aspect I noticed about the IMAP protocol specification is the
> "Internal Date Message Attribute" (INTERNALDATE).  The timestamps saved by
> OfflineIMAP seem to be the time it downloads them, not the INTERNALDATE
> timestamp, and the contents of the files are just the message body.  This
> seems to indicate that the INTERNALDATE is not saved.  Is this correct?  If
> so, why have the developers excluded INTERNALDATE from the migration?

Because of evil conspiracy. :-)
The "date" of a message is supposed to be stored in the mtime of a local
Maildir file in OfflineImap logic. I notice that we do not fetch the
INTERNALDATE when caching the list of messages from an IMAP server
though. So you are right. Given that this caching happens on every
folder sync, I guess it had been historically ommited for performance
reasons. It would make sense to retrieve and cache the INTERNALDATE of a
message, absolutely yes.

I'll add that to my mental TODO list.

> 2) What about the "UIDVALIDITY" value of folders?  Is this metadata merely
> lost in translation?  (The UID values of files are in the filenames, but the
> UIDVALIDITY of the folder is supposed to complement them.)

UIDVALIDITY is assigned by the server and has no other meaning that to
make sure that IDs are still valid. If you move your messages to a
different server, it is absolutely OK that the UIDVALIDITY changes.

> So, what else am I missing?  Is there any tool out there that
> *doesn't*throw away any metadata?

I just learned that imapsync isn't open source anymore. Pity...

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: not available
URL: <>

More information about the OfflineIMAP-project mailing list