As many of you know, WordPress depends upon a variety of software packages to do the things that it does, as a weblog product (and some of you have extended it even further…). Two of these things are foundational items: PHP, the language and operational runtime for WordPress, and MySQL, the persistence datastore that WordPress uses.
Both of these are being incremented upward to more current versions.
For many WordPress administrators, this will not be a dramatic issue, other than confirming your settings with your site host; some may require some configuration switches being “flipped” to use PHP 5.2 and MySQL 5.0.15. There may even be some adjustments to your site’s php.ini file.
However, if you’re a big-time hacker, and you’ve been coding in some changes to the base WordPress package (and who doesn’t these days, right?), then you will need to ensure that your code has not been exploiting some of the PHP 4 quirks that have changed in PHP 5 syntax: you will have to rewrite or redesign those parts of your code. For some developers, this endeavor may not be trivial.
On the other hand, the MySQL upgrade is generally better tolerated, since a lot of PHP developers tend to use the provided MySQL connector API. Again, however, if you are one of those who enjoys spinning up your own, parallel data persistence API or are using another package in addition to the WordPress one, you will have to ascertain the LoE for modifying your code. Also, if you have crafted some stored procedures for your MySQL 4 instance(s), you may have to re-implant them into your waiting MySQL 5 instance(s) once they are ready. Code-wise, it should be a straightforward import for most developers.
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Further reading of interest:
