When you log into the mobile app, if anything has changed within any of your assigned Projects since you last logged in, you'll see a red exclamation mark against that Project.
This allows you to quickly see any updates that have happened and jump right in to see what they are.
When you click into the Project, you can see which areas have new information in them. Any sections that contain updated information will also have the red exclamation mark.
When you jump into the highlighted section, anything new will be ringed in red to indicate what's changed.
The red rings will disappear once you've tapped on them to show that you've read them.