Notifying Clients of New Rates Electronically - Client Portal

We are trying to find the most efficient way to notify our clients of our 2019 rate changes in a timely manner.  We have some clients receiving electronic statements in the Client Portal and some receive paper statements.  

Is there a way to attach a file to the electronic statements that get sent to the Client Portal?  We need some kind of an efficient way of notifying these clients electronically and are open to all ideas.  

Thank you!