Added note on templates not being updated

docs/upgrading.rst

@@ -55,6 +55,14 @@ To apply the upgrade script do the following:
 
         patch -p1 < patchfile.diff
 
+5.  If you were using per-module template folders you need to move some
+    templates around.  Previously if you had a folder named ``templates``
+    next to a blueprint named ``admin`` the implicit template path
+    automatically was ``admin/index.html`` for a template file called
+    ``templates/index.html``.  This no longer is the case.  Now you need
+    to name the template ``templates/admin/index.html``.  The tool will
+    not detect this so you will have to do that on your own.
+
 Please note that deprecation warnings are disabled by default starting
 with Python 2.7.  In order to see the deprecation warnings that might be
 emitted you have to enabled them with the :mod:`warnings` module.
@@ -66,7 +74,6 @@ like svn, hg or git have builtin support for applying unified diffs as
 generated by the tool.  Check the manual of your version control system
 for more information.
 
-
 Bug in Request Locals
 `````````````````````