I have no decent words for the people who have allowed a reduction of items (e.g. a maximum of two emails) in the local Address Book. But it's happened and there's nothing I can do about it. My goal is to preserve as much information as possible without having to manually check every contact (about 1500) Current situation: - Thunderbird 91.2.1 Address Book - continuously updated, but with loss of some contact fields - Google Contact containing all fields (luckily gContactSync probably stopped working) but out of date (missing some new contacts and changes to existing ones) Target: - Thunderbird with CardBook add-on (vCard 4.0) - Nextloud for sharing contacts across my all devices (Linux including mobile) Any idea how to achieve this and not do unnecessary work?