Correct spelling of PHP 5.3?

Question

How do I write PHP and a version correctly? Is it with space separated or not?

PHP5.3 

or

PHP 5.3

If it is spelled with space, why do we say PHP5 then?

Answer 1

Also if I don't get your question at all there is the space Like: PHP 5.4

Take a look at:

PHP Site

Answer 2

Well, according to Zend, it's PHP 5.3 with a space - Reference