diff --git a/rebuild b/rebuild
index 1765569..7b48837 100644
--- a/rebuild
+++ b/rebuild
@@ -2,4 +2,4 @@
 # when dependencies of the charm change,
 # but nothing in the charm needs to.
 # simply change the uuid to something new
-91cb0fdc-a4d0-11ea-b69f-6f63bb868762
+d9db618c-d02c-11ea-8870-cf4b22eeb82f
diff --git a/src/files/.gitkeep b/src/files/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/test-requirements.txt b/test-requirements.txt
index 1c8aff7..0ab97f6 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -4,7 +4,7 @@
 #     https://github.com/openstack-charmers/release-tools
 #
 # Lint and unit test requirements
-flake8>=2.2.4
+flake8>=2.2.4,<=2.4.1
 stestr>=2.2.0
 requests>=2.18.4
 charms.reactive
diff --git a/tox.ini b/tox.ini
index 5b41c1d..afd48f0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -50,6 +50,11 @@ basepython = python3.7
 deps = -r{toxinidir}/test-requirements.txt
 commands = stestr run --slowest {posargs}
 
+[testenv:py38]
+basepython = python3.8
+deps = -r{toxinidir}/test-requirements.txt
+commands = stestr run --slowest {posargs}
+
 [testenv:pep8]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt