IMAPSieve Changed flags cause?

[MRob]

On 2017-04-05 18:50, MRob wrote:
> RFC 6785 says I should be able to run scripts when a command changes
> flags on a message but I can't understand what to put in
> imapsieve_mailboxXXX_causes. Dovecot logs something like STORE as an
> invalid cause.
> 
> How do I run an administrator Sieve script caused from change in flags?

Is no reply on this to mean the feature is not currently supported, or 
everyone's busy?

If not supported, are there plans to support admin scripts being 
triggered from message flag changes?