With ODF 1.4 the function EASTERSUNDAY becomes an ordinary, standardized function. This is tracked in OASIS in issue https://issues.oasis-open.org/browse/OFFICE-3851 LibreOffice needs to be adapted in some places. Tasks: The import needs to be changed to accept of:=EASTERSUNDAY in addition to of:=ORG.OPENOFFICE:EASTERSUNDAY. That change should be done to all active LibreOffice versions and on master. The export has to be changed to write of:=EASTERSUNDAY in case of save to ODF 1.4. That has to be done on master. Unit tests for import and export. The documentation in https://wiki.documentfoundation.org/Documentation/Calc_Functions/EASTERSUNDAY needs an update in section 'ODF standard' with remark 'since ODF 1.4'. I think this is an easyHack because only filters are affected and there exist a lot of examples in the code how to consider the ODF version.
(In reply to Regina Henschel from comment #0) > With ODF 1.4 the function EASTERSUNDAY becomes an ordinary, standardized > function. > This is tracked in OASIS in issue... https://issues.oasis-open.org/browse/OFFICE-2164