diff --git a/openstack/tools/charmed_openstack_functest_runner.sh b/openstack/tools/charmed_openstack_functest_runner.sh
index bea0c362..c36c94ec 100755
--- a/openstack/tools/charmed_openstack_functest_runner.sh
+++ b/openstack/tools/charmed_openstack_functest_runner.sh
@@ -12,6 +12,7 @@ MODIFY_BUNDLE_CONSTRAINTS=true
 REMOTE_BUILD=
 SKIP_BUILD=false
 SLEEP=
+USE_JUJU29=false
 WAIT_ON_DESTROY=true
 
 . $(dirname $0)/func_test_tools/common.sh
@@ -58,6 +59,9 @@ OPTIONS:
         enough capacity to boot the vms required by the tests.
     --sleep TIME_SECS
         Specify amount of seconds to sleep between functest steps.
+    --use-juju29
+        Configure the framework to use juju 2.9 instead of 3.x (usually
+        to be able to test bionic-based code)
     --help
         This help message.
 EOF
@@ -97,6 +101,9 @@ while (($# > 0)); do
             SLEEP=$2
             shift
             ;;
+        --use-juju29)
+            USE_JUJU29=true
+            ;;
         --help|-h)
             usage
             exit 0
@@ -154,8 +161,12 @@ export TEST_JUJU3=1
 # NOTE: this should not be necessary for > juju 2.x but since we still have a need for it we add it in
 export TEST_ZAZA_BUG_LP1987332=1
 
-# Some charms point to an upstream constraints file that installs python-libjuju 2.x so we need to do this to ensure we get 3.x
-export TEST_CONSTRAINTS_FILE=https://raw.githubusercontent.com/openstack-charmers/zaza/master/constraints-juju34.txt
+if $USE_JUJU29; then
+    export TEST_CONSTRAINTS_FILE=https://raw.githubusercontent.com/openstack-charmers/zaza/master/constraints-juju29.txt
+else
+    # Some charms point to an upstream constraints file that installs python-libjuju 2.x so we need to do this to ensure we get 3.x
+    export TEST_CONSTRAINTS_FILE=https://raw.githubusercontent.com/openstack-charmers/zaza/master/constraints-juju34.txt
+fi
 
 LOGFILE=$(mktemp --suffix=-charm-func-test-results)
 (
diff --git a/openstack/tools/openstack_regression_tests_runner.sh b/openstack/tools/openstack_regression_tests_runner.sh
index 8b470996..bdb11b18 100755
--- a/openstack/tools/openstack_regression_tests_runner.sh
+++ b/openstack/tools/openstack_regression_tests_runner.sh
@@ -6,6 +6,7 @@ FUNC_TEST_PR=
 FUNC_TEST_TARGET=
 IMAGES_PATH=$HOME/tmp
 MODIFY_BUNDLE_CONSTRAINTS=true
+USE_JUJU29=false
 
 . $(dirname $0)/func_test_tools/common.sh
 
@@ -25,6 +26,9 @@ OPTIONS:
         By default we modify test bundle constraints to ensure that applications
         have the resources they need. For example nova-compute needs to have
         enough capacity to boot the vms required by the tests.
+    --use-juju29
+        Configure the framework to use juju 2.9 instead of 3.x (usually
+        to be able to test bionic-based code)
     --help
         This help message.
 EOF
@@ -46,6 +50,9 @@ while (($# > 0)); do
         --skip-modify-bundle-constraints)
             MODIFY_BUNDLE_CONSTRAINTS=false
             ;;
+        --use-juju29)
+            USE_JUJU29=true
+            ;;
         --help|-h)
             usage
             exit 0
@@ -113,8 +120,12 @@ export TEST_JUJU3=1
 # NOTE: this should not be necessary for > juju 2.x but since we still have a need for it we add it in
 export TEST_ZAZA_BUG_LP1987332=1
 
-# Some charms point to an upstream constraints file that installs python-libjuju 2.x so we need to do this to ensure we get 3.x
-export TEST_CONSTRAINTS_FILE=https://raw.githubusercontent.com/openstack-charmers/zaza/master/constraints-juju34.txt
+if $USE_JUJU29; then
+    export TEST_CONSTRAINTS_FILE=https://raw.githubusercontent.com/openstack-charmers/zaza/master/constraints-juju29.txt
+else
+    # Some charms point to an upstream constraints file that installs python-libjuju 2.x so we need to do this to ensure we get 3.x
+    export TEST_CONSTRAINTS_FILE=https://raw.githubusercontent.com/openstack-charmers/zaza/master/constraints-juju34.txt
+fi
 
 # NOTE: this is the default applied in zaza-openstack-tests code but setting
 #       explicitly so we can use locally.