Build Forge Server 8.0.0.1 Agent compatibility with older version v7.1.1.3-0-0034

I have BF Server 7.1.2.1 talkingto  several remote Buildforge agents v7.1.1.3-0-0034 behind the firewall. I am planning to  install BF Server 8.0.0.1 in separate server and copy all projects from 7.1.2.1 to 8.0.0.1. My questions are related to agent compatibilities:

1. Is BF Server 8.0.0.1 backward compatible to Buildforge agents v7.1.1.3-0-0034.

2.  If answer to #1 is YES, because of this backward compatibilty, will I lose any of the new features which are there in BF Server 8.0.0.1 but require new version of agent ?

3. If answer to #1 is YES, can I use same agent for communicating with 2 different versions of servers ( 7.1.2.1 and 8.0.0.1). In our case since most of the agents are behind firewall, I prefer not to install separate agents unless it is must or unless we will be losing substantial feature for not having seperate agents.

4. If answer to #1 is NO, can 2 different versions of agents be installed on same VM instances (host).

Appreciate your prompt reply.