Hi, It looks like 32-bit data generated by 2021b is missing the effects of transitions below INT32_MIN. Before commit 93132d18, zones had a transition at INT32_MIN to the type in use at that time. For example, the Pacific/Port_Moresby zone used to have these two transitions: -2147483648 -> 1 (+10) 2147483647 -> 1 (+10) Starting with commit 93132d18, including in 2021b, only one transition is present: 2147483647 -> 1 (+10) Since clients are supposed to assume type 0 before the earliest transition, this almost always leads to wrong times for some period of time (or all times for extreme cases like Port Moresby). Danny -- Daniel Fischer Rastatt, Germany Oracle Global Services Germany GmbH