Paul, 1. For the record, I detest the practice of linking zones across different ISO-3166 regions. Forcing one country to be associated with another country is politically and culturally offensive. 2. In 2021b you have: Atlantic/Jan_Mayen linked to Europe/Berlin. Arctic/Longyearbyen linked to Europe/Oslo. This seems inconsistent to me. If you insist on keeping Atlantic/Jan_Mayen linked to Europe/Berlin, then I think that the Europe/Berlin entry in zone1970.tab should show "DE,SJ" instead of just "DE". -chris