Hi!
We are hoping to release this later this year.
Some more info regarding the matter: MUI upgrades affects both Create and new and existing Apps - so it is both crucial that the new versions are performant and that everything is tested thoroughly when included in Appfarm, and relevant new features in MUI must be implemented in Create. Appfarm is currently on MUI4, as the recent MUI5 upgrade needed to be rolled back due to technical reasons. We are on schedule with MUI6 however, and plan an upgrade later this year. However, MUI6 is not yet in stable release, but hopefully very soon.