I currently have Fairphone OS 18.04.01 installed on my FP2 (according to my Fairphone Update software) and it says the OS is up to date, though it is not.
Any ideas what to do here (if possible without a fresh installation which needs a data backup etc).
18.04.01 was the last Android 6 release before the upgrade. If I remember correctly you have to update the updater app in the app store to be able to upgrade, or you can manually install Android 7.