You can update Skylog from the Skylog web site. Download the update and install the update instead of the previous version (delete the previous installtion). Do not save the database in the Skylog installation folder. Otherwise the database may be lost after an update.
With Skylog 2.2.0 the database format has been changed. Migrate an older version by exporting flight logs and stundent logs and importing into the new version.
Preferences are lost after the update. Since Skylog 2.0 preferences can be exported and re-imported.
Updating automatically is no longer possible.