On the "Halls of Valhalla" site there's a new post the tries to explain the jump from PHP5 to PHP7 and what all that means for the language (and community around it).
Since around 2005 we've heard talk about PHP 6 development. There have even been books sold about it. But where is it? As of July of this year it was decided that there won't be one and that PHP will skip directly to version 7. Why is it skipping to the next major version, and what ever happened with PHP 6? And if we're already jumping to PHP 7, what kinds of features will it have?
They start with a "brief history" of PHP since its inception back in the mid 1990s and follow its evolution at a high level through the years. Then comes the topic of PHP6 and the work that was already being put towards it and integrated Unicode support. It talks about some of the difficulties of this conversion and the delays that ended up happening. Instead, it was decided that things would stay in the PHP 5.x series and 5.3, 5.4 and 5.5 have been created since. The jump to PHP7 came from this vote with several different reasons influencing the decision.
The post finishes with a look at some of the new things that will be coming in PHP7 including major performance improvements, abstract syntax tree functionality and asynchronous programming, allowing for the execution of parallel tasks in the same request.