Migrating Scalix to Google Apps: Mail

We are investigating Google Apps as a replacement for Scalix 11.4.6. I am doing a test migration right now that will move all my mail folders using (the older free version of) imapsync. Here is the script that I am using:

imapsync --host1 my.host1.com --user1 username --password1 **** --authmech1 PLAIN \
--host2 imap.gmail.com --user2 username --password2 **** --authmech2 LOGIN --port2 993 --ssl2 \
--exclude "Calendar|Contacts|Deleted Items|Journal|Junk E-mail|Notes|Other Users|Public Folders|Tasks" \
--prefix2 "SX/" --regexflag 's/\\X-*//g' --allowsizemismatch --useheader 'Message-ID' --skipsize

Let's go through the script:

These are the basic lines required for imapsync, specifying our hosts and login credentials.
imapsync --host1 my.host1.com --user1 username --password1 **** --authmech1 PLAIN \
--host2 imap.gmail.com --user2 username --password2 **** --authmech2 LOGIN --port2 993 --ssl2 \

This line excludes non-mail folders that will be moved manually, most likely via Outlook connectors & PST files. (ugh)
--exclude "Calendar|Contacts|Deleted Items|Journal|Junk E-mail|Notes|Other Users|Public Folders|Tasks"

This line will prefix each folder name is Google Apps with "SX". I want to keep migrated data separate from the default folders in Gmail.
--prefix2 "SX/"

This is required to fix an error with headers added by Scalix (BAD parse error: non-storable system tag "\X-Has-Attach"). See this post on the Zimbra forums.
--regexflag 's/\\X-*//g'

Since we are modifying the message (--regexflag, above) we need to tell imapsync to ignore message sizes, since they will no longer match. Instead, we need imapsync to use the "Message-ID" header to compare messages. These options allow us to run imapsync again after the intial sync and only sync changes.
--useheader 'Message-ID' --allowsizemismatch --skipsize

Big thanks to Mark for this post!