From Afaf El Maayati (2020-05-27):
In the Database file: ftp://ftp.iana.org/tz/tzdb-2020a/africa, it’s mentioned that a program will be running to implement the transition dates
That commentary refers to a program that I ran on April 14; it predicted daylight-saving transitions for Morocco for the years 2021 through 2087, and I installed those predictions into tzdb 2020a. We don't know now whether those predictions are correct, since the government of Morocco hasn't published plans for 2021 and later and it might change its mind before next year. Even so, the tzdb tradition is to predict plausible transitions that are more likely to be correct than a prediction of no transitions at all.
we will move to GMT+1 next Sunday, May 31.
Yes, that transition is in tzdb 2020a (the current tzdb release), so tzdb should not need any changes for it. Currently, devices based on out-of-date tzdb releases are off by an hour for Morocco; these devices should start being correct on May 31. Devices based on tzdb 2020a should be correct both now and after May 31. PS. Of the devices I have ready access to, many are out-of-date and are therefore showing incorrect time for Morocco because it takes more than a few weeks to propagate tzdb changes via manufacturers and suppliers to the billions of devices on the planet. My up-to-date devices are running: * Android 10 with APEX updates from Google Play Store * iOS 13.3.1 * macOS 10.14.6 * Ubuntu 18.04.3