Backport 2.5.3 release info to master branch. Bump version to 2.6.0a0.
diff --git a/NEWS b/NEWS
index b94a934..e074e4f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,13 @@
+Version 2.5.3
+-------------
+- Updated zoneinfo to 2016d
+- Fixed parser bug where unambiguous datetimes fail to parse when dayfirst is
+ set to true. (gh issue #233, pr #234)
+- Bug in zoneinfo file on platforms such as Google App Engine which do not
+ do not allow importing of subprocess.check_call was reported and fixed by
+ @savraj (gh issue #239, gh pr #240)
+- Fixed incorrect version in documentation (gh issue #235, pr #243)
+
Version 2.5.2
-------------
- Updated zoneinfo to 2016c