Hello, 1) when I create date on: 2017/03/20 (before Daylight Saving Time change) with this code: D1 := Date year: 2017 month: 3 day: 26. Date object is created with instvars: start: 2017-03-26T00:00:00+01:00 duration: 1:00:00:00 2) when I create same Date instance with the same code on/after: 2017/03/26 (after Daylight Saving Time change): D2 := Date year: 2017 month: 3 day: 26. Date instance with this instvars returned: start: 2017-03-26T00:00:00+02:00 duration: 1:00:00:00 3) D1 != D2 So, for example: persisted instance of date (Date year: 2017 month: 3 day: 26) created before DST change is not equal with date instance (Date year: 2017 month: 3 day: 26) created after DST change. DST change breaks equality of the same date :( Is it OK? Thanks! Petr Fischer