When you upgrade a standalone mongodb instance you can end up having the issue described below. When you have a version oldest than 4.4 in mongodb you should first upgrade to version 4.2 and then to version 4.4. During those steps however you must not forget to change the featureCompatibilityVersion. If you do not change this property mongodb will stop working.
"ctx":"initandlisten","msg":"Failed to start up WiredTiger under any compatibility version. This may be due to an unsupported upgrade or downgrade."}
Upgrade a Standalone to 4.4 — MongoDB Manual
You can get your current compatibility Version by using the mongo shell.
db.adminCommand( { getParameter: 1, featureCompatibilityVersion: 1 } )
In this end you should change your compatibility to 4.2 before upgrading to 4.4 in order for the upgrade to be performed successfully.
db.adminCommand( { setFeatureCompatibilityVersion: "4.2" } )
