Upgrading from 2019 Sage 50 Premium

SUGGESTED

Currently running 2019 Sage 50 Premium but someone else is taking the account over with their own computer. I see you can't bring files with you if you downgrade. 

Question is how does it work if we went to the cloud subscription. Do we have to get the 50c or can we do a different one that's cheaper. 

We really only use the following features: create invoices, reconcile bank account, and write cheques.