Notifications received a brand new design. They not only look better but it is now easier to see what changed on a related task and you can directly access the task detail without the need to leave the overlay window. That way you can respond much faster without the need to switch between workspaces.
In your MyView there is a new little but helpful option. You can now decide to hide subactivities. That way you can declutter your MyView by listing only the main activities.
Keeping your colleagues notified should be easy. On the bottom of any activity you can now make your colleagues to followers and so keeping them notified about changes and comments. Your team mates will now also become automatically follower if they add comment to activity or if they become assignee.