We’re introducing a new tasks experience in Outlook on the web powered by Microsoft To-Do. Customers who click the Tasks icon in the new Outlook on the web will now land in To-Do. This means that To-Do on the web will now be licensed through Exchange Online, rather than through To-Do plans. To-Do licenses will still continue access to To-Do for Windows, iOS and Android.
If you wish to continue managing access to To-Do on the web for your organization, we recommend considering the following options:
Update your tenant configuration to enable or disable the new Outlook on the web
Update your network configuration to allow or block access to https://to-do.office.com
Please note that executing step 2 while skipping step 1 might leave your end users with a poor experience, as there is a chance they will be opening the new Tasks experience which is powered by an app your network does not allow access to. They will then need to re-navigate to Mail or another feature and toggle "The new Outlook" off in order to access the classic Tasks experience.
Reminder: While To-Do on the web is no longer managed by To-Do licenses, the visibility of the tile in the app launcher does still depend on an enabled To-Do license.