diff --git a/bindep.txt b/bindep.txt
index ba2ccb4b..de0f66ef 100644
--- a/bindep.txt
+++ b/bindep.txt
@@ -2,3 +2,4 @@ libxml2-dev [platform:dpkg test]
 libxslt1-dev [platform:dpkg test]
 build-essential [platform:dpkg test]
 zlib1g-dev [platform:dpkg test]
+libffi-dev [platform:dpkg]
diff --git a/test-requirements.txt b/test-requirements.txt
index 89f4ce00..20c7b68d 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -47,3 +47,8 @@ tempest<31.0.0;python_version<'3.8' and python_version>='3.6'
 tempest<24.0.0;python_version<'3.6'
 
 croniter            # needed for charm-rabbitmq-server unit tests
+
+jsonschema<4.18.0   # jsonschema 4.18.0 depends on Rust (via rpds-py)
+
+# needed for py36 due to openstacksdk>=0.18.0->python-ironicclient->zaza.openstack
+platformdirs<2.5.0;python_version<'3.7'