Joost de Valk published to his blog this morning about a mistake he made with an update to his WordPress SEO plugin. He used a feature in PHP that isn’t supported in PHP 5.2, and therefore his plugin didn’t work on a massive number of websites that are running out of date PHP (as he noted, PHP 5.2 hasn’t been supported by PHP in over two years). His lessons learned is a good read, and a good note of warning to other developers releasing WordPress plugins. It’s not exciting that it takes so long for some hosts to adopt modern PHP versions, but it’s a reality that we live in on such an open system. Also, props to Joost for owning up and sharing his lessons learned with others.