Puzzles me in 2017c: Africa/Juba and backzone/Africa/Juba differ in their astronomical longitudes: in zone1970.tab: SS +0451+03137 Africa/Juba in zone.tab: SS +0451+03136 Africa/Juba and (correspondingly) in the local mean time used before the switch to zone time in 1931: in africa: Zone Africa/Juba 2:06:28 - LMT 1931 in backzone: Zone Africa/Juba 2:06:24 - LMT 1931 Why? And do we need the backzone entry at all? Michael Deckers. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus