Thanks for the letter. The current TZDB release (2022g) should be correct for timestamps in Greenland until 2024-03-30 since we already knew about the 2023 changes, and the next TZDB release (which should be out soon) should match your letter's contents completely for timestamps into the indefinite future. We currently have the Ittoqqortoormiit area one hour ahead of Nuuk, i.e., Ittoqqortoormiit is UTC -1 during winter and is UTC during summer, observing EU-style daylight saving time. If this is incorrect or if Ittoqqortoormiit changes its rules, please let us know.