diff --git a/stack.sh b/stack.sh
index dc79fa9..0c01165 100755
--- a/stack.sh
+++ b/stack.sh
@@ -173,7 +173,7 @@
 
 # Warn users who aren't on an explicitly supported distro, but allow them to
 # override check and attempt installation with ``FORCE=yes ./stack``
-if [[ ! ${DISTRO} =~ (precise|trusty|utopic|vivid|7.0|wheezy|sid|testing|jessie|f20|f21|f22|rhel7) ]]; then
+if [[ ! ${DISTRO} =~ (precise|trusty|utopic|vivid|7.0|wheezy|sid|testing|jessie|f21|f22|rhel7) ]]; then
     echo "WARNING: this script has not been tested on $DISTRO"
     if [[ "$FORCE" != "yes" ]]; then
         die $LINENO "If you wish to run this script anyway run with FORCE=yes"