6
The following is based on MAMP releases which bundle the Zend Optimizer with PHP (2 versions) and MySQL.
PHP Version(s) Zend Optimizer
4.4.4 + 5.2.0 3.2.2
4.4.4 + 5.1.6 3.0.1
4.4.2 + 5.1.4 2.6.0
4.4 + 5.0.4 2.5.10
4.3.11 + 5.0.4 2.5.7
4.3.9 + 5.0.2 2.5.5
4.3.7 2.5.5
MAMP appear to have skipped 2.6.2 in favour of 3.0.1 for use with PHP 4.4.4, but 2.6.2 may be fine.
I also could not find an 'official' compatibility list anywhere. This is frustrating as I believe using the wrong version can indeed cause problems.
HTH
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