Nextcloud version: 30.0.0
Operating system and version : SmartOS
Apache or nginx version: nginx 1.26.2
PHP version: 8.2
Mail: 4.0
Watching the Hub 9 demo at 4361s there’s a snazzy UI presented that lets the user add some sieve filtering. How do I access this UI? I don’t see anywhere how to create these rules except to hand edit the sieve filter rules I have in an embedded text editor.
Sorry, the feature didn’t make it into Mail 4.0.
We will release it as soon as possible.
Work in progress on GitHub: https://github.com/nextcloud/mail/pull/10135
It’s sad it made it into the marketing, but I am happy that I can at least edit my sieve rules directly. Thank you!
This was the main reason for me to update to NC30 
Is there already an estimated date?
Lol literally same here. Being here now, I am bummed at how slow Nextcloud Mail loads mail from IMAP. It seems like it is fetching whole mailboxes almost each time. It’s significantly slower than Thunderbird, by massive amounts. Otherwise I am impressed how far the UI has come.
The nice sieve editing UI, I am very excited for. At least now I can go in and edit my sieve script directly, but it is the actual sieve file. Which is okay for me, but I want to have the new UI present so other users can enjoy the benefits without having to know sieve
Our plan is to release Mail 4.1 in the last week of October.
Hi there,
The pull request for the mail filters is merged, but we cannot release a new version because of a regression with the menus for the accounts.
I will let you know once I know more, sorry!
Mail 4.1 is out 
It took a bit longer because we were facing issues after migrating our JavaScript bundler.
Please let us know what you think, and also what features for the filter UI you are missing.