WordPress 5 is available today. The headline feature is the new Gutenberg editor.
This is perhaps the biggest single-day release in the history of open source software. That’s no exaggeration. I’m unable to think of any other change that was so significant and was quickly pushed out to over 30% of the web.
PHP versions impact over 50% of the web, but they take years to roll out. 3 years after the launch of PHP 7, more than half of PHP servers are still running PHP 5.