I’ve a 3.4 MongoDB cluster with tree nodes :
- node01 : Primary
- node02 : Secondary
- node03 : Secondary
Currently I have upgraded the version on all nodes to 3.6.x but i’ve kept the featureCompatibility version to be 3.4 only.
I need to know what will be the impact of changing the featureCompatibility version to 3.6. It needs to be done as it is one of the prerequisite to upgrade the servers to 4.0.x
And hence I won’t be able to downgrade the feature compatibility version it makes it a difficult task if things go wrong.
Need more insights about the featureCompatibility version in MongoDB and what are the best practices around the same.
Also it’ll be helpful if I can get list of known issue people face while moving from 3.4 to 3.6.