diff --git a/package-lock.json b/package-lock.json
index 19701ee00b06..754eab06ed33 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
     "name": "python",
-    "version": "2026.8.0",
+    "version": "2026.9.0-dev",
     "lockfileVersion": 2,
     "requires": true,
     "packages": {
         "": {
             "name": "python",
-            "version": "2026.8.0",
+            "version": "2026.9.0-dev",
             "license": "MIT",
             "dependencies": {
                 "@iarna/toml": "^3.0.0",
diff --git a/package.json b/package.json
index 84442dbe2898..bd0bab53bebf 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
     "name": "python",
     "displayName": "Python",
     "description": "Python language support with extension access points for IntelliSense (Pylance), Debugging (Python Debugger), linting, formatting, refactoring, unit tests, and more.",
-    "version": "2026.8.0",
+    "version": "2026.9.0-dev",
     "featureFlags": {
         "usingNewInterpreterStorage": true
     },