Teams Now Tells You About Planner Task Assignments
In an update posted to the Microsoft Technical Community on May 15, Microsoft announced that Teams running in enterprise and education tenants now creates notifications in user activity feeds for Planner task assignments. According to Microsoft, the new feature is available from May 16 (it works in my tenant). There’s no word when this feature might be available in Office 365 sovereign clouds.

Notifications Only for Integrated Plans
Notifications appear when people are assigned tasks using the Planner browser interface, the Planner mobile app, the SharePoint web part for Planner, or when a plan is integrated in Teams via a channel tab. The last point is important because a plan must be integrated with Teams before Planner knows that it needs to generate notifications. Adding a plan to a tab also adds the Planner bot, and it is the bot that posts messages to assignees. Teams treats the messages from the Planner bot like new messages from any other personal chat and flags them to the activity feed, which is how the notifications arrive. And like any other personal chat, the messages sent by the Planner bot also appear under Chats. Figure 1 shows notifications in both the activity feed and chat pane. The list of notifications in the Planner chat is a convenient way to make sure that you don’t miss an assigned task.
Notifications show up in the mobile clients too. Figure 2 shows two Planner notifications in the activity feed in a Teams for iOS client. The Planner bot is a little more obvious in this client as you see the offer to “chat with Planner.” Clicking this link brings you to the set of chats received from the Planner bot. If you click a Planner notification, the link brings you to the task in the Planner app (assuming it is installed on the device). I haven’t tested what happens when the Planner app is unavailable but assume that the link opens Planner in a browser.

Each notification includes the name of the assigned task, the person who assigned the task, the name of the plan, and a link to open Planner in the channel tab. Marking a task complete in Planner doesn’t remove a notification.
Notification Settings
Notifications only show up in Teams if an assignee’s Planner settings allow them (Figure 3). A small but important point…

Learn more about Planner in Chapter 15 of the Office 365 for IT Pros eBook. How to integrate Planner in a Teams channel tab is covered in Chapter 13.
I’m very interested in having these updates. We’re on a o365 E3 plan. Any update when this feature will be updated?
The feature should be there now.