I suggest creating a link above Help Center named "News" or "COB Updates" where you can communicate to the community using your platform different changes, updates and improvement. For example a new coin got listed, it could be beneficial for all your users.

Furthermore I believe that as you are going to expand your exchange to fiat currency. I believe that a lot of new users will perhaps not be interested in cryptocurrency and it could be a great way to promote the coins that you list on your exchange which would have been based on research and trust. Therefore, it will attract more new users and it would be great for existing users as well.