I've been thinking about this and we can actually make this work very easily. There's 3 things that need to be done.
1. Connect internally to
http://www.arc-engine.com/version.php?edition=EDITION (where EDITION can be "Legacy" or left out for the normal version) which will basically return the version string of the newest ARC version of the given edition.
2. After getting the version string of the current version, it will be compared with the current ARC version and if the new version is higher than the current one, a dialog will pop up informing the user that the new version X.Y.Z is available. There will be 2 buttons: "Update now" and "Close".
2. If the user clicks on the "Update now" button, just run this in Python:
try:
os.system("start http://www.arc-engine.com/update.php")
except:
pass
This will open the default browser and take the user to the ARC download page where he can download the newest version.
Additionally it would be good if there was an option in ARC "Check for updates on every start up" and a menu option "Check for new version" in the "Help" sub-menu so people can turn it off if it's annoying them.
Sure, this may not be the nicest solution, but why complicate things? Tons of programs do it this way, including highly regarded and commercially used programs such as Tortoise SVN.