I’ve been playing with this recently as well and it looks like somewhere down the road between versions the required datetime format changed from a string that looks like “YYYY-MM-DD HH:MM:SS” to an epoch value (the number of seconds since Jan 01, 1970 00:00:00 UTC)
I’m having issues with timezone support (CS is converting all my input to UTC despite it being input in my local timezone) but hopefully this will help you.