I can see that Icinga Agent 2.15.0 is is available for Windows.
There is a different departement who is responsible for the Icinga console/server in our company, and they are a little behind. it looks like they are on version 2.12.1.
At the moment we are running Icinga Agent version 2.14.6 on Windows servers.
Is the 2.15.0 agent compatible with Icinga server 2.12.1, or do we need to wait until the the Icinga server is upgraded?
In general, this should not work. Icinga 2 aims to be compatible with one older minor version in the direction of master to satellite/agent or satellite to agent. Please take a look at the versions and upgrade section.
Furthermore, if this team still runs Icinga 2.12.1, please urge them to upgrade since there are (at least) two potentially critical security vulnerabilities in this version: