update basic client

I have a basic account and today when I tried to log on it said that I needed to update the client or use the web version - this has never happened before and i cannot find a way to update the client - I am running version 5.9.3931 and it appears as though version 5.13 is the latest  and thoughts as I followed the on-line guide from zoom but i go not have a "general tab" in settings that would allow be to set auto update