I built a PHP 5 app back in ~2007 that's still in active use today. My hosting provider emailed me at some point saying that they would force-upgrade the server

I built a PHP 5 app back in ~2007 that's still in active use today. My hosting provider emailed me at some point saying that they would force-upgrade the server to PHP 8 for security reasons. It took less than 2 hours of effort to update all of the code to work with the latest version.