On the Engine Yard blog Davey Shafik has a new post celebrating ten years of PHP 5 as of July 13th, 2014:

Ten years ago yesterday on July 13th 2004, PHP 5.0.0 was unleashed onto the world. Bringing with it the Zend Engine 2, effectively a brand new PHP. [...] The truth is that until PHP 5, PHP was a mostly procedural language, while it supported classes and objects, they were a bolt-on feature. This history is still visible in the majority of its default feature set even today — including some of its newest additions like the new password hashing API.

He talks about the evolution of PHP even since version 5.0.0 and how other technologies, like Ruby on Rails, has influenced the language and its developers towards greater things. He shares his answers to a few questions including:

What is the most significant change to PHP in the last 10 years?
• What's the biggest change in the community in the last 10 years?
• What's the most pressing issue for PHP?
• What would you like to see in the next major version?

He also includes an infographic of the timeline that lead up to the PHP 5.0.0 release and the advancements since then. There's even a look at the "Future of PHP" with some emerging technologies and what might lie in store for "PHP 6" (whatever that may end up being).