This documentation contains information about both PHP 4 and PHP 5, with
some added migration and compatibility notes regarding PHP 3. Behaviour,
parameter, return value and other changes between different PHP
versions are documented in notes and inline text in the manual.
Documentation partly exists for the CVS version of PHP, which
always means the very latest development version. This has yet to
be released so is only available through the CVS version handling system,
or via a snapshot. So be aware that
features marked "available in CVS" are typically unavailable. These
features, though, will most likely be available in the next stable version
of PHP. To download the CVS version, see the anonymous
CVS access page.
Also, documentation may exist for PHP versions that aren't yet released.
(something like PHP 5.0.0 while the latest stable version
is 4.3.x). Most of the time, this is not an error in the documentation.
Explanation is often added for features not available in the current
PHP release, but will be available as a known future PHP version.
Typically, PHP only adds new features in major releases otherwise only bugs
are fixed. Using the A.B.C versioning format, a major release increments A
or B whereas minor releases increment C. So for example it's not uncommon
for a feature to be documented as available in PHP x.1.x when the latest
release is PHP x.0.x. Also note that the manual is written in present
tense, not future tense.
Many times the PHP manual lists "Default Values" for PHP directives. These
values are based on php.ini_dist and not
php.ini_recommended. They also refer to the latest
version of PHP. See the PHP directive
appendix for details on these values and changes.