In case you're wondering how to do the whole thing in RM or have looked at "old" examples, I think the below would be a relatively simple way to do it:
Trigger: Contact closed
Actions:
IF (Private Boolean is False) THEN
Set Private Boolean True
Notify "%device% has been closed"
END-IF
Cancel Delayed Actions
Wait for events: Contact opened
Delay 0:05:00 (cancelable)
Set Private Boolean False
Notify "%device% has been open for 5 minutes!"
If you want the "repeat" functionality from Notifier, it gets a bit more complicated, but not too much. I always recommend this post from Bruce with examples of how to do repeated notifications in RM.
