The problem is related to an out of date FileMaker Go App that doesn’t work with the new iOS. Go to the App store and look for a more recent version.
The ‘logbook9.fmp12’ logbook file will then need to be transferred to this new FMG app. If you have a recent backup this is easily emailed back to your iPhone as an attachment. You will then be given the option to open the file in the newer App.
Otherwise you can pull it from the old FMG App using third party backup software such as iMazing (https://imazing.com) which you should be able to download for a PC or Mac to link up with your iPhone.