diff --git a/lib/platform/azure/index.ts b/lib/platform/azure/index.ts
index 52414ad774f868d49e0339e5b99ceb8ea9fb2e7a..8b98d93bf6dde87bc09779913ce27982ce106c73 100644
--- a/lib/platform/azure/index.ts
+++ b/lib/platform/azure/index.ts
@@ -383,13 +383,11 @@ export /* istanbul ignore next */ function commitFilesToBranch({
   branchName,
   files,
   message,
-  parentBranch = config.baseBranch,
 }: CommitFilesConfig): Promise<string | null> {
   return config.storage.commitFilesToBranch({
     branchName,
     files,
     message,
-    parentBranch,
   });
 }
 
diff --git a/lib/platform/bitbucket-server/index.ts b/lib/platform/bitbucket-server/index.ts
index ca495e9c0520529117f044412959713ed4b71c19..f5d83c27ae379dc066dccd5d1d6d7f3f93eaafcb 100644
--- a/lib/platform/bitbucket-server/index.ts
+++ b/lib/platform/bitbucket-server/index.ts
@@ -430,7 +430,6 @@ export async function commitFilesToBranch({
   branchName,
   files,
   message,
-  parentBranch = config.baseBranch,
 }: CommitFilesConfig): Promise<string | null> {
   logger.debug(
     `commitFilesToBranch(${JSON.stringify(
@@ -438,7 +437,6 @@ export async function commitFilesToBranch({
         branchName,
         filesLength: files.length,
         message,
-        parentBranch,
       },
       null,
       2
@@ -448,7 +446,6 @@ export async function commitFilesToBranch({
     branchName,
     files,
     message,
-    parentBranch,
   });
 
   // wait for pr change propagation
diff --git a/lib/platform/bitbucket/index.ts b/lib/platform/bitbucket/index.ts
index bba4830bafa9d15f03d6c592482ffe0a097c9a16..2ec87005bd6e8d2f6ce166cfce0c9596db93e47c 100644
--- a/lib/platform/bitbucket/index.ts
+++ b/lib/platform/bitbucket/index.ts
@@ -292,13 +292,11 @@ export function commitFilesToBranch({
   branchName,
   files,
   message,
-  parentBranch = config.baseBranch,
 }: CommitFilesConfig): Promise<string | null> {
   return config.storage.commitFilesToBranch({
     branchName,
     files,
     message,
-    parentBranch,
   });
 }
 
diff --git a/lib/platform/common.ts b/lib/platform/common.ts
index 38bc9031532c9c9826f87ea6af0bdf609396d891..a270c2383c55bbb5e979d1d8c231500b8f26be32 100644
--- a/lib/platform/common.ts
+++ b/lib/platform/common.ts
@@ -27,7 +27,6 @@ export type CommitFilesConfig = {
   branchName: string;
   files: File[];
   message: string;
-  parentBranch?: string;
 };
 
 export interface GotApiOptions {
diff --git a/lib/platform/git/storage.spec.ts b/lib/platform/git/storage.spec.ts
index 2a299e636b425b1ec8bf83921d96d545374e63c9..01a035519d27d9475dae12623d732aeb227ab0f8 100644
--- a/lib/platform/git/storage.spec.ts
+++ b/lib/platform/git/storage.spec.ts
@@ -162,20 +162,6 @@ describe('platform/git/storage', () => {
     it('should throw if branch merge throws', async () => {
       await expect(git.mergeBranch('not_found')).rejects.toThrow();
     });
-    it('should throw if branch merge is stale', async () => {
-      expect.assertions(1);
-      await git.setBranchPrefix('renovate/');
-      await git.commitFilesToBranch({
-        branchName: 'test',
-        files: [{ name: 'some-new-file', contents: 'some new-contents' }],
-        message: 'test mesage',
-        parentBranch: 'renovate/past_branch',
-      });
-
-      await git.setBaseBranch('master');
-
-      await expect(git.mergeBranch('test')).rejects.toThrow();
-    });
   });
   describe('deleteBranch(branchName)', () => {
     it('should send delete', async () => {
@@ -209,7 +195,7 @@ describe('platform/git/storage', () => {
       ).rejects.toMatchSnapshot();
     });
   });
-  describe('commitFilesToBranch({branchName, files, message, parentBranch})', () => {
+  describe('commitFilesToBranch({branchName, files, message})', () => {
     it('creates file', async () => {
       const file = {
         name: 'some-new-file',
diff --git a/lib/platform/git/storage.ts b/lib/platform/git/storage.ts
index fe4838b3dbcf9a31d2f460d5b235bfda80bba740..19fe8d6692f77488874f4006433eaa57f0492bd9 100644
--- a/lib/platform/git/storage.ts
+++ b/lib/platform/git/storage.ts
@@ -468,13 +468,16 @@ export class Storage {
     branchName,
     files,
     message,
-    parentBranch = this._config.baseBranch,
   }: CommitFilesConfig): Promise<string | null> {
     logger.debug(`Committing files to branch ${branchName}`);
     try {
       await this._git.reset('hard');
       await this._git.raw(['clean', '-fd']);
-      await this._git.checkout(['-B', branchName, 'origin/' + parentBranch]);
+      await this._git.checkout([
+        '-B',
+        branchName,
+        'origin/' + this._config.baseBranch,
+      ]);
       const fileNames = [];
       const deleted = [];
       for (const file of files) {
diff --git a/lib/platform/gitea/index.spec.ts b/lib/platform/gitea/index.spec.ts
index 1ab1a02d09f6bbbb8d724a7289f2c124ef9dfd85..e9724382eb3c2edd7f048ba9b66c130260507ebc 100644
--- a/lib/platform/gitea/index.spec.ts
+++ b/lib/platform/gitea/index.spec.ts
@@ -1453,24 +1453,8 @@ index 0000000..2173594
       expect(gsmCommitFilesToBranch).toHaveBeenCalledTimes(1);
       expect(gsmCommitFilesToBranch).toHaveBeenCalledWith({
         ...commitConfig,
-        parentBranch: mockRepo.default_branch,
       });
     });
-
-    it('should propagate call to storage class with custom parent branch', async () => {
-      const commitConfig: CommitFilesConfig = {
-        branchName: 'some-branch',
-        files: [partial<File>({})],
-        message: 'some-message',
-        parentBranch: 'some-parent-branch',
-      };
-
-      await initFakeRepo();
-      await gitea.commitFilesToBranch(commitConfig);
-
-      expect(gsmCommitFilesToBranch).toHaveBeenCalledTimes(1);
-      expect(gsmCommitFilesToBranch).toHaveBeenCalledWith(commitConfig);
-    });
   });
 
   describe('getPrBody', () => {
diff --git a/lib/platform/gitea/index.ts b/lib/platform/gitea/index.ts
index bc47b23f13438afe434eab7d30c2d301e5b02c0c..a3c70bcb1014b98048a5b653ae85eb20c64fb283 100644
--- a/lib/platform/gitea/index.ts
+++ b/lib/platform/gitea/index.ts
@@ -891,13 +891,11 @@ const platform: Platform = {
     branchName,
     files,
     message,
-    parentBranch = config.baseBranch,
   }: CommitFilesConfig): Promise<string | null> {
     return config.storage.commitFilesToBranch({
       branchName,
       files,
       message,
-      parentBranch,
     });
   },
 
diff --git a/lib/platform/github/index.ts b/lib/platform/github/index.ts
index 108fb6460242de327873678328876ea6d46e3dcd..9187981ea806a409efcb3eb74e80dec29c9c69d1 100644
--- a/lib/platform/github/index.ts
+++ b/lib/platform/github/index.ts
@@ -558,13 +558,11 @@ export function commitFilesToBranch({
   branchName,
   files,
   message,
-  parentBranch = config.baseBranch,
 }: CommitFilesConfig): Promise<string | null> {
   return config.storage.commitFilesToBranch({
     branchName,
     files,
     message,
-    parentBranch,
   });
 }
 
diff --git a/lib/platform/gitlab/index.ts b/lib/platform/gitlab/index.ts
index 2e0a380576aad4a6ecc37a915fa68da3af4ead8a..9208cfdf1aa5668de12057d036e5c41ab634071f 100644
--- a/lib/platform/gitlab/index.ts
+++ b/lib/platform/gitlab/index.ts
@@ -591,13 +591,11 @@ export function commitFilesToBranch({
   branchName,
   files,
   message,
-  parentBranch = config.baseBranch,
 }: CommitFilesConfig): Promise<string | null> {
   return config.storage.commitFilesToBranch({
     branchName,
     files,
     message,
-    parentBranch,
   });
 }
 
diff --git a/lib/workers/branch/__snapshots__/commit.spec.ts.snap b/lib/workers/branch/__snapshots__/commit.spec.ts.snap
index 8fe48a4992415f3a913aa743dbba2e53e6a35f2e..7f4762af4e70eb1b95554650a56fa170d7b24b06 100644
--- a/lib/workers/branch/__snapshots__/commit.spec.ts.snap
+++ b/lib/workers/branch/__snapshots__/commit.spec.ts.snap
@@ -12,7 +12,6 @@ Array [
         },
       ],
       "message": "some commit message",
-      "parentBranch": undefined,
     },
   ],
 ]
diff --git a/lib/workers/branch/commit.ts b/lib/workers/branch/commit.ts
index 0d8418ffbfaed95a00ff3162593edb9340484cff..86f71984d16e477b8e3f1d5b447a81a170c8acf0 100644
--- a/lib/workers/branch/commit.ts
+++ b/lib/workers/branch/commit.ts
@@ -37,6 +37,5 @@ export async function commitFilesToBranch(
     branchName: config.branchName,
     files: updatedFiles,
     message: config.commitMessage,
-    parentBranch: config.baseBranch || undefined,
   });
 }