I thought it was reverse compatible ?
May be it is.
But it is not a thing, that is tested : A lot of things will / can
go wrong, when the system python is changed.
None of the administrative tools can be updated when python-2.4.3 is missing.
The rpm date base used by yum will be confused by a wrong version added by force.
( # 'yum localinstall python-2.7<etc.>rpm' would never work.)
A thing to try : # 'rpm -e python' will show the connected packages.