Notes when upgrading to PHP5

I upgraded one of my servers to PHP5 this morning. Two things to watch out for:

  • The location of your php.ini may have changed. It’s probably now in /etc/php5/apache2/. You need to copy over any changes from your old one.
  • Update your libraries too such as the mysql client and the gd library. Don’t forget you can delete the old ones. apt-get install php5-mysql php5-gd will do the job of installing, the old packages have a php4 prefix.
  • WP-Cache doesn’t like PHP5 much. If you see a blank page after upgrading to PHP5, then hit reload and it loads, then WP-Cache needs to be modified. Leroy has the fix, open wp-cache-phase2.php in your wp-cache folder and change ob_end_clean() to ob_end_flush(). SImple as that!

The reason for the upgrade? I wanted to install the gd extension, but after lots of fun upgrading everything my browser tried to download every page, complaining that it was a phtml file. I chose the upgrade to PHP5 to fix it!

And finally, the reason for gd, was to get the heatmap in this wordpress click tracking plugin working. It’s like Crazy Egg and it works well, but I couldn’t get it to display a heatmap for any page other than the front page. Some of the comments on Daily Blog Tips where I found it are hilarious. They completely miss the point of using a heatmap!