Call out supported versions. Closes #3232.

docs/topics/3.2-announcement.md

@@ -32,6 +32,12 @@ Also note that this is an initial release and we do not yet have a public API fo
 
 The idea is to get this released to users early, so we can start getting feedback and release a more fully featured version in 3.3.
 
+## Supported versions
+
+This release drops support for Django 1.4.
+
+Our supported Django versions are now 1.5.6+, 1.6.3+, 1.7 and 1.8.
+
 ## Deprecations
 
 There are no new deprecations in 3.2, although a number of existing deprecations have now escalated in line with our deprecation policy.