The 5th tab of Top Eleven game is the News.
All the new updates will appear inside the News. It's like your daily newspaper, a notification center for you. Usually when there's notification, a bubble with number will appear. This will indicate the number of new news.
When you go inside, you'll be able to see all the Read and Unread news.
As you can see from my News, I've just signed 2 new players. It'll appear there for me to know. There are other news such as players injury and suspension. If you sold any players, it'll be there too.
A piece of advise: Just have a quick glance before you decide to do anything. It'll help you to plan your next better move.