Mac OS X-PHP on Mac OS X Note: There is an known incompatibility between PHP 4.1 and MacOS X version 10.1.2. If you need to compile PHP 4.1 from the source code, you can employ the work around found at http://www.entropy.ch/software/ macosx/php/. See NOTE 2 of the Build Instructions. You can also find a pre-compiled binary at the same location. This article currently covers installation of PHP 4.0.6.