clarify supported python versions in two docs. Reported by Joseph Myers.

Author: rouilj

CHANGES.txt

@@ -7,9 +7,8 @@ Each entry has the developer who committed the change in brackets.
 Entries without name were done by Richard Jones.
 
 **IMPORTANT** The v1.5.x releases of Roundup were the last to support
-Python v2.5. Support for Python v2.5 is dropped starting with the v1.6.x
-releases of Roundup, at which point v2.7.2 is required to run those
-releases of Roundup.
+Python v2.5 and v2.6.  Starting with the v1.6 releases of Roundup
+v2.7.2 is required to run newer releases of Roundup.
 
 
 201?-??-??: 1.6.0

doc/upgrading.txt

@@ -11,10 +11,9 @@ then you don't need to do anything. If you're upgrading from 0.5.6 to
 0.6.8 though, you'll need to check the "0.5 to 0.6" and "0.6.x to 0.6.3"
 steps.
 
-**IMPORTANT** The v1.5.x releases of Roundup will be the last to
-support Python v2.5. Support for Python v2.5 and v2.66 will be dropped
-with the v1.6 release of Roundup. Roundup 1.6 and newer require
-Python v2.7.
+**IMPORTANT** The v1.5.x releases of Roundup were the last to support
+Python v2.5 and v2.6.  Starting with the v1.6 releases of Roundup
+v2.7.2 is required to run newer releases of Roundup.
 
 Contents: