To answer your question, we are currently building a system that will allow you to upgrade your FusionAuth Cloud deployment anytime. This should be available soon and if you setup a FusionAuth Cloud account before then, we will upgrade it to this new system once it is ready.
In the meantime, if you ever need an upgrade on your deployment, all you need to do is open a support ticket and we’ll schedule that upgrade with you.
We aren’t planning on releasing a major version of FusionAuth for a while (this would be version 2.0). We do release a number of minor versions with new features and bug/security fixes each year though.