I think we need a public compliance test, similar to html and ssl, then people would start questioning the quality of their own client, and migrate to better ones. When Micro$oft will eventually feel the pinch, then they will start fixing their $hit. People have the power! (I like that song.)

>
> As I have no control over their minds, hands, and client software, I wish I could enforce the policy from the server, returning an
> error message to the client. 
>
> On its turn, this requires the client to listen to such server messages, operated by a smarter user. 

the problem with pseudomail pseudoprogram outlook is that it simply
ignores error and shows folder created, then even allow to store messages
in it (store it locally in temporary file).

When file is deleted messages are lost.


>
> At the end of the day, it feels like we are re-discovering the wheel, as such problems should have been addressed and solved long
> ago by an RFC. 
>
> Listescape is a welcome patch. Let see if it works. I just have to select a character that no user could type and still practical
> for the filesystem to use...
>
>
> On Mon, Oct 1, 2018 at 10:07, Timo Sirainen <tss@iki.fi> wrote:
> On 28 Sep 2018, at 16.44, Wojciech Puchar <wojtek@puchar.net> wrote:
>
> user attempts to create folders with / dovecot naturally cannot create it so it returns error but outlook of
> course "create" it and keep data in local store only. data is lost when you remove local store .pst file.
>
> The question is - can dovecot be configured so it will automatically replace slash in name with something
> else?
>
>
> https://wiki2.dovecot.org/Plugins/Listescape maybe?
>
>
>