Merge pull request #5271 from benjaoming/docs-windows-upgrade

Add a known issue for Windows upgrades from 0.15 due to #5263

Author: benjaoming

docs/installguide/release_notes.rst

@@ -1,6 +1,8 @@
 Release Notes
 =============
 
+.. warning::
+
 0.16.9
 ------
 
@@ -17,6 +19,11 @@ Known issues
  * Windows installer tray application option "Run on start" does not work see `learningequality/installers#106 <https://github.com/learningequality/installers/issues/106>`__
  * Writing to ``server.log`` is disabled on Windows :url-issue:`5057`
  * Installing on Windows 8, 32bit is reported to take ~1 hour before eventually finishing.
+ * If you are upgrading from 0.15 on a Windows system, you have to manually locate
+   ``python-packages\ka-lite``, typically in
+   ``C:\Python27\share\kalite\python-packages\requests`` and delete it. Otherwise
+   video download breaks. :url-issue:`5263`
+
 
 **Paper cuts**