diff --git a/stack.sh b/stack.sh
index 38ecceb..8e05ae6 100755
--- a/stack.sh
+++ b/stack.sh
@@ -143,7 +143,7 @@
 
 # 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|7.0|wheezy|sid|testing|jessie|f19|f20|rhel6|rhel7) ]]; then
+if [[ ! ${DISTRO} =~ (precise|trusty|7.0|wheezy|sid|testing|jessie|f19|f20|f21|rhel6|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"