diff --git a/app/release-controller/src/selfUpgrade.ts b/app/release-controller/src/selfUpgrade.ts
index 5f8dd02b..da023d7a 100644
--- a/app/release-controller/src/selfUpgrade.ts
+++ b/app/release-controller/src/selfUpgrade.ts
@@ -36,7 +36,8 @@ export const buildReleaseControllerDefinition = (
     name: CONTROLLER_PROCESS_NAME,
     script: path.join(workspaceRoot, 'app', 'release-controller', 'dist', 'index.js'),
     cwd: path.join(workspaceRoot, 'app', 'release-controller'),
-    args: ['daemon'],
+    // The CLI defaults to daemon. Omitting a one-element args array avoids PM2
+    // serializing it as the literal `["daemon"]` during an in-process self-upgrade.
     env: {
         ...sanitizeManagedProcessEnv(config.baseEnv),
         GATEWAY_DATABASE_URL: config.gatewayDatabaseUrl,
diff --git a/app/release-controller/test/releaseController.test.ts b/app/release-controller/test/releaseController.test.ts
index 3cd4a2b6..aeb56f8e 100644
--- a/app/release-controller/test/releaseController.test.ts
+++ b/app/release-controller/test/releaseController.test.ts
@@ -445,8 +445,8 @@ describe('upgradeReleaseController', () => {
         expect(starts.at(-1)).toMatchObject({
             name: 'sammo:release-controller',
             cwd: path.join(workspace, 'app', 'release-controller'),
-            args: ['daemon'],
         });
+        expect(starts.at(-1)?.args).toBeUndefined();
     });
 
     it('restores the old controller definition when the new daemon cannot start', async () => {