diff --git a/bindep.txt b/bindep.txt
new file mode 100644
index 0000000..17575d9
--- /dev/null
+++ b/bindep.txt
@@ -0,0 +1,4 @@
+libffi-dev [platform:dpkg]
+libpq-dev [platform:dpkg]
+libxml2-dev [platform:dpkg]
+libxslt1-dev [platform:dpkg]
diff --git a/requirements.txt b/requirements.txt
index a68620f..c539e82 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,7 +10,7 @@ setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb
 
 # Build requirements
 cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.
-charm-tools==2.8.3
+charm-tools==2.8.4
 
 simplejson
 
diff --git a/src/test-requirements.txt b/src/test-requirements.txt
index b7075b2..7c26a08 100644
--- a/src/test-requirements.txt
+++ b/src/test-requirements.txt
@@ -8,5 +8,5 @@
 tox
 
 # Functional Test Requirements (let Zaza's dependencies solve all dependencies here!)
-git+https://github.com/openstack-charmers/zaza.git@stable/21.10#egg=zaza
-git+https://github.com/openstack-charmers/zaza-openstack-tests.git@stable/21.10#egg=zaza.openstack
+git+https://github.com/openstack-charmers/zaza.git@stable/yoga#egg=zaza
+git+https://github.com/openstack-charmers/zaza-openstack-tests.git@stable/yoga#egg=zaza.openstack
diff --git a/test-requirements.txt b/test-requirements.txt
index 4afbb28..4ceaedf 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -50,3 +50,6 @@ pbr==5.6.0       # vault
 cryptography<3.4 # vault, keystone-saml-mellon
 lxml             # keystone-saml-mellon
 hvac             # vault, barbican-vault
+
+# Pin urllib3 for py35 unit tests
+urllib3<=1.26.7;python_version<'3.6'
diff --git a/tox.ini b/tox.ini
index 2d60b8a..5505605 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,6 +23,7 @@ requires =
   pip < 20.3
   virtualenv < 20.0
   setuptools<50.0.0
+  tox < 4.0.0
 
 # NOTE: https://wiki.canonical.com/engineering/OpenStack/InstallLatestToxOnOsci
 minversion = 3.18.0
@@ -96,7 +97,7 @@ commands = stestr run --slowest {posargs}
 [testenv:pep8]
 basepython = python3
 deps = flake8==3.9.2
-       charm-tools==2.8.3
+       charm-tools==2.8.4
 commands = flake8 {posargs} src unit_tests
 
 [testenv:func-target]