Hi
See the announcement here: Question - eramba MySQL and PHP versions required? (due for 20th March)
Same applies to redhat enterprise linux. Redhat is very cautious with upgrading to new version, so we still are on a lower version, even though these versions are quite old already.
I guess there are some enterprises using RHEL or Debian thus it might be good to not speed up too much on this requirement (which is my corporate opinion… personally I think that the integration of new versions is too slow on RHEL) .