In https://github.com/10gen/mongo/pull/48030 I am adding a check to ensure server parameters are not removed between releases. 

The following parameters do not exist in master but exist in 8.2

• "planRankerMode"

 Action items:
1. If we are confident that no production clusters use this parameter we can keep it ignored forever just edit the comment. (Or comment on the PR if it is still open)
2. Add back the deprecated parameter as a stub, see this commit as an example
3. If the parameter was renamed, put the old parameter name in the "deprecated name" field of the new parameter.

https://github.com/10gen/mongo/blob/master/buildscripts/idl/compatibility_rules.yml