Disable ModernUI

This bug is marked as resolved since Thu, 03 Feb 2022 06:22:06 GMT.
However, it’s not possible (AFAIK and the support doesn’t give a way to do it either - case 01318650) to disable ModernUI.

There is a variable (zimbraPrefClientType) that contains the current UI the user has chosen (standard,advanced,modern).

But it’s not possible to totally disable (per CoS and/or domain) the choice of the ModernUI.

Being able to disable ModernUI would allow to upgrade to ZCS 9.x (or 10.x, the day it becomes possible) from 8.8.15 without having to deal with the ModernUI issues (users lost in the new interface, additional support to provide to users, missing features, etc)

ZBUG-1861 is now converted to ZRFE-1236