Changing IMAP separator - does it break things?

[Filip Hajný]

14. 10. 2020 v 11:28, Markus Winkler <ml at irmawi.de>:
> 
> Hi Victor,
> 
> On 14.10.20 04:36, Victor Sudakov wrote:
>> Do you think I can change the hierarchy separator in the "inbox"
>> namespace without breaking other clients and the mail layout on disk,
>> losing mail etc?
> 
> I personally would try to avoid such a change (really IMHO), especially if it's "only":
> 
>> I don't want to break mail for 50 people just to please one Mac Mail
>> user.
> 
> _one_ user. Could Thunderbird or another IMAP client be an option for this single user? And perhaps Apple can tell some details when their Mail client will be standards-compliant?
> 
> Besides that: changing the hierarchy separator is generally possible. But you schould try and check that with a test system to prevent problems with your productive environment and all the other users.
> 

I had to do it with 10-20 live users and it went fine, nobody noticed anything (I made the change in the night hours just to be sure though). I had to go down and fix some erratic folder names that resulted from the botched separator handling on some macOS Mail accounts.

The funny thing is that I set up a vanilla Dovecot server elsewhere and subfolders worked fine there on the very same macOS client. Couldn’t find any significant difference in the configs that would explain the problem, also the relative lack of similar reports out there seemed mind boggling.

(I’m using the Dovecot-based Mailcow mail stack for production, which makes troubleshooting a little more challenging.)

-F