When upgrading the MongoDB server community edition from a very old version to the newest version one cannot skip installing intermediate versions, e. g. version 3.6 -> 4.4 does not work because the database files cannot be auto-migrated and the FeatureCompatibilityVersion is too low on 3.6 (or not existent).

Instead we have to install 3.6 -> 4.0 -> 4.2 -> 4.4 and execute db.adminCommand( { setFeatureCompatibilityVersion: "..." } ) appropriately in between installing each new version.

I propose creating an additional installer package for Linux which takes care of all that to migrate the internal database structure from the installed version to the latest but recent version available to apt - including setting FeatureCompatibilityVersion. This "upgrade-package" would contain all files necessary to upgrade from 3.6 -> 4.2 (in my example) so that the upgrade from 3.6 to 4.4 would not fail.