After you install this update, there's no change in the behavior of the Group Policy, the functionality is still the same. The only change that has occurred is that the policy explanation is updated in the August update for Do not allow users to enable or disable add-ons.
There's no exception for Do not allow users to enable or disable add-ons policy. When you enable this policy, none of the add-ons can be manged by the user.
See the following details of the policy explanation.
After this update
This policy setting allows you to manage whether users have the ability to allow or deny add-ons through Add-On Manager.
If you enable this policy setting, users cannot enable or disable add-ons through Add-On Manager.
If you disable or don't configure this policy setting, the appropriate controls in the Add-On Manager will be available to the user.
Before this update
This policy setting allows you to manage whether users have the ability to allow or deny add-ons through Add-On Manager.
If you enable this policy setting, users cannot enable or disable add-ons through Add-On Manager. The only exception occurs if an add-on has been specifically entered into the Add-On List policy setting in such a way as to allow users to continue to manage the add-on. In this case, the user can still manage the add-on through the Add-On Manager.
If you disable or do not configure this policy setting, the appropriate controls in the Add-On Manager will be available to the user.