Description:
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The PHP Documentation mixes documentation, functions, etc from many different versions of PHP -- PHP4, 5, and 5.1.

The PHP documentation one year ago was an excellent reference.  It is now difficult to sort out which parts are relevant to the version of PHP you are working with.

While many of us wish to upgrade to the "latest and greatest" PHP, there are constraints placed upon us which do not allow this to happen (such as applications depending on a particular version, or hosting providers stuck at a version).

Expected result:
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The PHP manual should be organised similar to the way the MySQL manual has been organised (See http://dev.mysql.com/doc/).

The MySQL manual has been separated into versions 3.2.3 through 4.1 (which have similar functionality), 5.0, and 5.1.

A similar setup would allow for far easier navigation through the PHP manual for those of us who are "stuck" at an earlier version.