diff --git a/lib/manager/bundler/index.ts b/lib/manager/bundler/index.ts
index bcb44731b29ad993664e80bd7326cb557412f9d3..5024b9831cfa242c717cddffc80f0dc82a77f862 100644
--- a/lib/manager/bundler/index.ts
+++ b/lib/manager/bundler/index.ts
@@ -1,5 +1,4 @@
 import { extractPackageFile } from './extract';
-import { updateDependency } from './update';
 import { updateArtifacts } from './artifacts';
 import { getRangeStrategy } from './range';
 import { LANGUAGE_RUBY } from '../../constants/languages';
@@ -18,7 +17,6 @@ export {
   updateArtifacts, // Optional
   getRangeStrategy, // Optional
   language, // Optional
-  updateDependency, // Mandatory
 };
 
 export const defaultConfig = {
diff --git a/lib/manager/bundler/update.spec.ts b/lib/manager/bundler/update.spec.ts
deleted file mode 100644
index 962827e6ea2143d0da3ac5e0a589cfd5f1deffdb..0000000000000000000000000000000000000000
--- a/lib/manager/bundler/update.spec.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-import { readFileSync } from 'fs';
-import { updateDependency } from './update';
-
-const railsGemfile = readFileSync(
-  'lib/manager/bundler/__fixtures__/Gemfile.rails',
-  'utf8'
-);
-
-describe('manager/docker-compose/update', () => {
-  describe('updateDependency', () => {
-    it('replaces existing value', () => {
-      // gem "rack-cache", "~> 1.2"
-      const upgrade = {
-        managerData: { lineNumber: 13 },
-        depName: 'rack-cache',
-        newValue: '~> 1.3',
-      };
-      const res = updateDependency({
-        fileContent: railsGemfile,
-        upgrade,
-      });
-      expect(res).not.toEqual(railsGemfile);
-      expect(res.includes(upgrade.newValue)).toBe(true);
-    });
-    it('returns same', () => {
-      // gem "rack-cache", "~> 1.2"
-      const upgrade = {
-        managerData: { lineNumber: 13 },
-        depName: 'rack-cache',
-        newValue: '~> 1.2',
-      };
-      const res = updateDependency({
-        fileContent: railsGemfile,
-        upgrade,
-      });
-      expect(res).toEqual(railsGemfile);
-    });
-    it('returns null if mismatch', () => {
-      // gem "rack-cache", "~> 1.2"
-      const upgrade = {
-        managerData: { lineNumber: 13 },
-        depName: 'wrong',
-        newValue: '~> 1.3',
-      };
-      const res = updateDependency({
-        fileContent: railsGemfile,
-        upgrade,
-      });
-      expect(res).toBeNull();
-    });
-    it('uses single quotes', () => {
-      const upgrade = {
-        managerData: { lineNumber: 0 },
-        depName: 'rack-cache',
-        newValue: '~> 1.3',
-      };
-      const gemFile = `gem 'rack-cache', '~> 1.2'`;
-      const res = updateDependency({ fileContent: gemFile, upgrade });
-      expect(res).toEqual(`gem 'rack-cache', '~> 1.3'`);
-    });
-    it('returns null if error', () => {
-      const res = updateDependency({ fileContent: null, upgrade: null });
-      expect(res).toBeNull();
-    });
-  });
-});
diff --git a/lib/manager/bundler/update.ts b/lib/manager/bundler/update.ts
deleted file mode 100644
index 7e3bcb1363db73bf54a2cc6c7f9b25aa178952a3..0000000000000000000000000000000000000000
--- a/lib/manager/bundler/update.ts
+++ /dev/null
@@ -1,43 +0,0 @@
-import { logger } from '../../logger';
-import { UpdateDependencyConfig } from '../common';
-
-/*
- * The updateDependency() function is mandatory, and is used for updating one dependency at a time.
- * It returns the currentFileContent if no changes are necessary (e.g. because the existing branch/PR is up to date),
- * or with new content if changes are necessary.
- */
-
-export function updateDependency({
-  fileContent,
-  upgrade,
-}: UpdateDependencyConfig): string | null {
-  try {
-    const delimiter =
-      fileContent.split('"').length > fileContent.split("'").length ? '"' : "'";
-    const lines = fileContent.split('\n');
-    const lineToChange = lines[upgrade.managerData.lineNumber];
-    if (!lineToChange.includes(upgrade.depName)) {
-      logger.debug('No gem match on line');
-      return null;
-    }
-    const newValue = upgrade.newValue
-      .split(',')
-      .map((part) => `, ${delimiter}${part.trim()}${delimiter}`)
-      .join('');
-    const newLine = lineToChange.replace(
-      new RegExp(
-        `(gem ${delimiter}[^${delimiter}]+${delimiter})(,\\s+${delimiter}[^${delimiter}]+${delimiter}){0,2}`
-      ),
-      `$1${newValue}`
-    );
-    if (newLine === lineToChange) {
-      logger.debug('No changes necessary');
-      return fileContent;
-    }
-    lines[upgrade.managerData.lineNumber] = newLine;
-    return lines.join('\n');
-  } catch (err) {
-    logger.debug({ err }, 'Error setting new Gemfile value');
-    return null;
-  }
-}