## DateTime in Mysql JCB Settings
In Joomla 3 we were used to setting the default for a datetime field to 0000-00-00 00:00:00. Since J4 (because of the mysql 8.0 requirement) that is no longer a valid default value. So it should be set to NULL. 

To do so, you would change your field settings to these:

Data default = Other\
Other Default = EMPTY\
Null switch = NULL