diff --git a/package.json b/package.json
index 171f788..18f560b 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "name": "testpilot-containers",
   "title": "Containers Experiment",
   "description": "Containers works by isolating cookie jars using separate origin-attributes defined visually by colored ‘Container Tabs’. This add-on is a modified version of the containers feature for Firefox Test Pilot.",
-  "version": "0.9",
+  "version": "0.9.0",
   "author": "Andrea Marchesini, Luke Crouch and Jonathan Kingston",
   "bugs": {
     "url": "https://github.com/mozilla/testpilot-containers/issues"
diff --git a/webextension/manifest.json b/webextension/manifest.json
index be8f2f7..095eec6 100644
--- a/webextension/manifest.json
+++ b/webextension/manifest.json
@@ -1,7 +1,7 @@
 {
   "manifest_version": 2,
   "name": "Containers Experiment",
-  "version": "0.9",
+  "version": "0.9.0",
 
   "description": "Containers works by isolating cookie jars using separate origin-attributes defined visually by colored ‘Container Tabs’. This add-on is a modified version of the containers feature for Firefox Test Pilot.",
   "icons": {