Downgrading from 2.4.x to 2.3.x (testing only)

[Thomas Jarosch]

Hi Bron,

I'm currently testing the upgrade path from 2.3.16 to 2.4.17.
Everything is smooth so far, mailbox indexes were upgraded
automatically after starting 2.4.17 for the first time:

--------------------------
Dec 18 13:48:00 ctl_cyrusdb[14851]: checkpointing cyrus databases
Dec 18 13:48:00 ctl_cyrusdb[14851]: done checkpointing cyrus databases
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.admin (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.admin.Entw&APw-rfe (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.admin.Gel&APY-schte Elemente (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.admin.Gesendete Elemente (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.cyrus (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.mueller (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.mueller.Entw&APw-rfe (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.mueller.Gel&APY-schte Elemente (10 -> 12)
Dec 18 13:48:00 cyr_expire[14850]: Index upgrade: user.mueller.Gesendete Elemente (10 -> 12)
--------------------------


For the fun of it (doing it for science!) I downgraded again to 2.3.16
while keeping the new index files. Every access to the mailbox via IMAP
was blocked with "Future index version xxx". Good.

-> So the indexes are protected against a downgrade without a reconstruct.


Will mailboxes.db / annotations.db also stay fine after a downgrade?

I don't think there are any data structure differences between 2.3.x and 2.4.x
in there but I thought I'd better ask.

Cheers,
Thomas