diff --git a/datetime.md b/datetime.md
new file mode 100644
index 0000000..119488e
--- /dev/null
+++ b/datetime.md
@@ -0,0 +1,7 @@
+## 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
\ No newline at end of file