Not Happening.
PHP 5.3.29 was released on 14 Aug 2014, which incidentally, was the last version of PHP 5.3 ever to be released. Any bugs and security issues since then have remained unfixed in your version of PHP.
Since then, PHP 5.4, 5.5, 5.6 and now even 7.0 have been released, all fixing major bugs, improving performance, and closing many security holes.
I've chosen to not support out of date versions of PHP as a form of encouraging you to contact your web host and ask for something more recent, *anything* more recent.
PHP 5.4 and 5.5 are no longer officially supported by PHP for security patches either I should add. I'll be reviewing if I should bump the requirements to PHP 5.6 probably next year.