Qcodo already is using some things that are not compatible with php versions < 5.2 .
An example of this is the function “memory_get_peak_usage” used on line 64 of codegen.cli.php, the Pdo drivers or the Soap server implementation.
I'm pretty sure that there are other incompatibilities too.
I really doubt that somebody is using a new version of qcodo with a php version of more than 4 years ago.
If we end support for php versions lower than 5.2, we could not only erase some old code (fewer bugs :) ) but also get rid of some ugly hacks like :
if (version_compare(PHP_VERSION, '5.1.0') == -1)
(QQuery.class.php line 54)
Furthermore we can take advantage of new functions, classes, etc...
Here's a list of some php 5.2 advantages:
http://www.php.net/manual/en/migration52.php
Just my two cents...
Cheers,
Marcos