I’ve started to see this topic come up again and again lately. PHP4 is *not* in Feisty Fawn’s repositories at all and has been completely replaces by PHP5. It’s been discussed a few times in the forums, and I suspect it will continue to pop up occasionally. You can always look in the mailing lists to see this topic discussed.
PHP4 hasn’t been supported for the last 3 releases (but it was packaged and in the repositories), and it seems most of the major distributions have also stopped providing it. PHP4 has many well-known security issues, since PHP5 has been in the wild for over 4 years, and most big hosting companies are moving towards it.
Personally, I’m not sure if I agree with removing it completely (and without making a more public announcement), I still use PHP4 in all my production servers (Ubuntu Dapper’s and Fedora’s, and my company develops for PHP4, so this is a bit of a complication.
I guess it’s time to move on.