Hello

We are considering the server and client agent upgrade. Currently we are running server at 9.6 and agent on 8.12.0.26. I'm wondering if you could share any insight if the change plan covers everything that might happen

Server upgrade process sounds rather easy:
1. backup database
2. VM snapshot
3. Stop services on main server and proxy server
4. Run upgrade on main server (next next next) 
5. Run upgrade on proxy server
6. Start services
7. Test

Agent upgrade: 
1. Find out the proper switch to run upgrade unattended
2. Roll out using deployment software

Several questions are in the background: how are agents and servers compatible with each other? Can older agent successfully talk to a newer server? Are there any magic prerequisites that we need to complete? Have you heard about any major outages with such upgrade? 

Thanks in advance!

AlexP