The PHP 3.0 Apache module no longer supports Apache versions prior to 1.2. Apache 1.2 or later is required.
In PHP/FI 2.0, an implementation side-effect caused $foo to have the same effect as $foo. This is not true for PHP 3.0.
Reading arrays with $array is no longer supported
Also, $array1 = $array2 does not append the values of $array2 to $array1, but appends $array2 as the last entry of $array1. See also multidimensional array support.
"+" is no longer overloaded as a concatenation operator for strings, instead it converts it's arguments to numbers and performs numeric addition. Use "." instead.