Minimum requirements

I thought the idea was a rapid release of converted 1.11b for J2.5 and then work on JEM for J3+ am I wrong here?

Sure. But the direction is clear. This way we can drop support for old Jooma versions and clean up messy code, which, in the end, could make us faster

What do you think of a requiring a minimum PHP version of 5.3?
Some new code functionalities could be used.

PHP 5.3+ is what J2.5 recommends, but its minimum requirement is 5.2.4. PHP 5.2.x is end-of-life since end of 2010 though.

J3.x requires PHP 5.3.1+

See: docs.joomla.org/Technical_requirements

Considering what you wrote about J2.5 I think a minimum requirement of PHP 5.3 is fair.

Ok, I add it to the installer check script. I use version PHP version 5.3.1 though to match the J3.x requirements.