I wonder how this will work with used phones purchased privately. I bought a phone on craigslist that was locked to T-Mobile. It wasn't blacklisted so I'm able to use it on T-Mobile, but I don't know if the contract was paid in full, the original account is in good standing, etc.
Suggestion: Check the version against the latest release and kindly notify visitors if a newer release is available. Provide the link to make it easy to upgrade.
I've often had family and friends ask me why some site or service doesn't work but they don't know if their browsers are up to date. I would love to start by directing them to a site like this and telling them to upgrade if they aren't using the latest version of their browser.