Subscribe on item change

Hi At some point i think I noticed a community project adding functionality to let a user "subscribe" to item updates. We have users who ask for functionality so they can select to subscribe on by instance a specific part to let them receive an email every time this part, ECO or whatever is updated. Does anyone have information about this old community project or have anyone tried to build such functionality? Best Regards Henrik Olesen Kamstrup A/S Denmark