Upgrade 19.1 to 21 bring Calendar PHP error
Using Softalicious to upgrade https://cidoc-dswg.org/wiki/ from 19.1 to 21 I get this error:
'' The following errors were found :
Required PHP extension not found : calendar''
There are 9 PHP files with calendar or calendars in their file name in the current installation.
Any suggestions as to what is missing and how to fix it so I can complete the upgrade?
Many thanks,
:Jonathan