Why so old firefox in 5.1?

[Jeronimo Baldino]

Hi,

I just want to know: why OpenBSD provides Firefox 9.0.1 in packages when 
the latest stable release (12.0, according to Mozilla) was launched in 
April 24, 2012.

Why older versions (3.5.19, 3.6.25) are still shipped with ?

Thank you,
JB