I have two things in place.
Just a normal, run of the mill wordpress site, userspice.com
A downloadable php script called UserSpice that is used for managing users/controlling access to pages, etc. It's a complete PDO/OOP rewrite of UserCake. It is going through a lot of updates and features are being added weekly. UserSpice 4 has a dashboard for the administrator to administrate things. I would like the dashboard to be able to phone home to UserSpice.com to check what the latest version of UserSpice (the php app) is and offer to download the update.
I have searched extensively, but most searches involve updating the php version, NOT the app itself. Is there a particular phone home api or something like that which is built specifically for this purpose. I would assume it would involve just putting a version.txt or xml file in the root of userspice.com that contains the current version, but ideally I would want it to phone home at some sort of interval so as not to bring the userspice.com server down with useless requests.