[Users] affects of changing compatibility setting on running cluster

[Charles Weber]

Hi everyone, 
I believe I need to change my cluster compatibility level and would like to know if I can do this ona live cluster or if I have to change everything to maintenance mode first.

I ran engine setup and upgraded to current engine level then tried to add a new node using the 3.3.4 el6 iso. This resulted in an error:

Host x.x.x.x is installed with VDSM version (4.14) and cannot join cluster Default which is compatible with VDSM versions [4.13,4.9,4.11,4.12,4.10].

My current versions are:
Engine 3.3.4-1.el6 at compatibiltiy version 3.2

2 Nodes running CentOS 6.4 with VDSM 4.10.3-0.36.23.el6

Am I correct that I need to change the compatibility version to 3.3?
This has some production VMs, do I need to turn everything off first or is this a non-interruptive change?
How will this upgrade affect my current 2 hosts at their version?

My original idea was to migrate working VMs to new ovirt ISO node and then re-install original nodes to the same version off the 3.3.4 el6 iso.

I appreciate any advice.
Chuck