Section 9
The Free Software Foundation may publish revised and/or new
versions of the General Public License from time to time. Such
new versions will be similar in spirit to the present version, but
may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If
the Program specifies a version number of this License which
applies to it and any later version
, you have the
option of following the terms and conditions either of that
version or of any later version published by the Free Software
Foundation. If the Program does not specify a version number of
this License, you may choose any version ever published by the
Free Software Foundation.