It doesn't seem like this is currently possible without polling, but it would be useful so we could indicate to users that the page isn't installed, and do things like notify users if they a date is approaching where they would need to have it installed.
It doesn't seem like this is currently possible without polling, but it would be useful so we could indicate to users that the page isn't installed, and do things like notify users if they a date is approaching where they would need to have it installed.