If you run a cluster based on Jgroups with members running on a different micro version these members are compatible. Sometime even changes in minor versions are compatible. Thats why you can configure Jgroups to disable the version check with the global config property VERSION_CHECK. That's fine so far

Usually you have other software running which is using Jgroups. In our case it's infinispan. Infinispan itself is not compatible in major/minor or micro (patch) version

If we start up a new version of our software with a new infinispan version, the following thing happens: the first new member is sending incompatible infinispan messages to another member which is still running an older version. As we only have different versions while deploying a new software, it would be nice to discard all messages if the version of jgroups differ. 

The problem is described on stackoverflow in detail

In our situation we should only have to different versions of jgroups running  when we are in the middle of an upgrade process.

The patch I will attach to this issue shortly addresses this issue. A new config  property VERSION_CHECK_MICRO is introduced which defaults to false. If set to true and VERSION_CHECK is true (which is the default) messages will be discarded if they are not from the exact same jgroups version.

This helps in some situations. But in some way it solves a problem which is not in the domain of jgroups. So I can't say that I really like it.