diff --git a/.ng-dev-config.ts b/.ng-dev-config.ts
index 3950d40f26f1..e028981d40d9 100644
--- a/.ng-dev-config.ts
+++ b/.ng-dev-config.ts
@@ -1,6 +1,6 @@
 import {MergeConfig} from '@angular/dev-infra-private/pr/merge/config';
+import {determineMergeBranches} from '@angular/dev-infra-private/pr/merge/determine-merge-branches';
 import {GithubConfig} from '@angular/dev-infra-private/utils/config';
-import {determineMergeBranches} from './scripts/determine-merge-branches';
 
 /**
  * Github configuration for the ng-dev command. This repository is
@@ -16,7 +16,11 @@ const github: GithubConfig = {
  * are respected by the merge script (e.g. the target labels).
  */
 const merge = (): MergeConfig => {
-  const {minor, patch} = determineMergeBranches(github.owner, github.name);
+  const currentVersion = require('./package.json').version;
+  // We use the `@angular/cdk` as source of truth for the latest published version in NPM.
+  // Any package from the monorepo could technically work and result in the same version.
+  const {minor, patch} = determineMergeBranches(currentVersion, '@angular/cdk');
+
   return {
     // By default, the merge script merges locally with `git cherry-pick` and autosquash.
     // This has the downside of pull requests showing up as `Closed` instead of `Merged`.
diff --git a/package.json b/package.json
index d0391f446fcd..d11a088db235 100644
--- a/package.json
+++ b/package.json
@@ -43,7 +43,6 @@
     "resync-caretaker-app": "ts-node --project scripts/tsconfig.json scripts/caretaking/resync-caretaker-app-prs.ts",
     "ts-circular-deps:check": "yarn -s ts-circular-deps check --config ./src/circular-deps-test.conf.js",
     "ts-circular-deps:approve": "yarn -s ts-circular-deps approve --config ./src/circular-deps-test.conf.js",
-    "ng-dev": "ts-node -O {\\\"module\\\":\\\"commonjs\\\"} ./node_modules/@angular/dev-infra-private/cli.js",
     "merge": "ng-dev pr merge",
     "approve-api": "node ./scripts/approve-api-golden.js"
   },
@@ -71,7 +70,7 @@
     "@angular-devkit/schematics": "^10.0.0-next.6",
     "@angular/bazel": "^10.0.0-rc.0",
     "@angular/compiler-cli": "^10.0.0-rc.0",
-    "@angular/dev-infra-private": "https://github.com/angular/dev-infra-private-builds.git#7f3e1227d199a55943152aac6119d40e1bbb028f",
+    "@angular/dev-infra-private": "https://github.com/angular/dev-infra-private-builds.git#2ac83eb462cb25c46a761d34dec030e360055016",
     "@angular/platform-browser-dynamic": "^10.0.0-rc.0",
     "@angular/platform-server": "^10.0.0-rc.0",
     "@angular/router": "^10.0.0-rc.0",
diff --git a/scripts/determine-merge-branches.ts b/scripts/determine-merge-branches.ts
deleted file mode 100644
index ce52120d0182..000000000000
--- a/scripts/determine-merge-branches.ts
+++ /dev/null
@@ -1,66 +0,0 @@
-import {join} from 'path';
-import * as semver from 'semver';
-import {exec} from 'shelljs';
-
-/** Regular expression that matches remote head refs. */
-const UPSTREAM_HEAD_REF = /refs\/heads\/(.*)$/;
-
-/** Determines merge branches based on the current project version. */
-export function determineMergeBranches(
-    owner: string, name: string): {minor: string, patch: string} {
-  const projectRoot = join(__dirname, '../');
-  const currentVersion = semver.parse(require('../package.json').version);
-
-  if (currentVersion === null) {
-    throw Error('Cannot parse version set in project "package.json" file.');
-  }
-
-  const {major, minor, patch, prerelease} = currentVersion;
-  const isMajor = minor === 0 && patch === 0;
-  const isMinor = minor !== 0 && patch === 0;
-
-  // If there is no prerelease, then we compute patch and minor branches based
-  // on the current version major and minor.
-  if (prerelease.length === 0) {
-    return {minor: `${major}.x`, patch: `${major}.${minor}.x`};
-  }
-
-  // If current version is set to a minor prerelease, we can compute the merge branches
-  // statically. e.g. if we are set to `9.3.0-next.0`, then our merge branches should
-  // be set to `9.x` and `9.2.x`.
-  if (isMinor) {
-    return {minor: `${major}.x`, patch: `${major}.${minor - 1}.x`};
-  } else if (!isMajor) {
-    throw Error('Unexpected version. Cannot have prerelease for patch version.');
-  }
-
-  // If we are set to a major prerelease, we cannot statically determine the stable
-  // patch branch (as the latest minor segment is unknown). We determine it by looking
-  // for existing patch branches upstream.
-  const upstreamRefs = exec(
-                           `git ls-remote --heads https://github.com/${owner}/${name}.git`,
-                           {silent: true, cwd: projectRoot})
-                           .trim()
-                           .split('\n');
-
-  // Iterate over retrieved upstream refs in reverse. Git sorts them lexicographically ascending.
-  // We are interested in the greatest semver version starting with the given prefix.
-  for (let i = upstreamRefs.length - 1; i >= 0; i--) {
-    const matches = upstreamRefs[i].match(UPSTREAM_HEAD_REF);
-    if (matches === null) {
-      continue;
-    }
-    const branchName = matches[1];
-    const branchVersion = branchName.split('.');
-
-    // Look for the most recent stable branch that has been created before the new major
-    // prerelease version. e.g. if the current major is `10.0.0-next.0`, then we need to
-    // look for a previous patch branch that matches `9.{minor}.x`.
-    if (branchVersion[0] === `${major - 1}` && branchVersion[1] !== 'x' &&
-        branchVersion[2] === 'x') {
-      return {minor: `${major - 1}.x`, patch: branchName};
-    }
-  }
-
-  throw Error('Could not determine merge branches.');
-}
diff --git a/yarn.lock b/yarn.lock
index b3988afda0a8..81fe82875185 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -92,9 +92,9 @@
   dependencies:
     tslib "^1.9.0"
 
-"@angular/dev-infra-private@https://github.com/angular/dev-infra-private-builds.git#7f3e1227d199a55943152aac6119d40e1bbb028f":
+"@angular/dev-infra-private@https://github.com/angular/dev-infra-private-builds.git#2ac83eb462cb25c46a761d34dec030e360055016":
   version "0.0.0"
-  resolved "https://github.com/angular/dev-infra-private-builds.git#7f3e1227d199a55943152aac6119d40e1bbb028f"
+  resolved "https://github.com/angular/dev-infra-private-builds.git#2ac83eb462cb25c46a761d34dec030e360055016"
   dependencies:
     "@octokit/graphql" "^4.3.1"
     chalk "^2.3.1"
@@ -103,6 +103,7 @@
     inquirer "^7.1.0"
     minimatch "^3.0.4"
     multimatch "^4.0.0"
+    semver "^6.3.0"
     shelljs "^0.8.3"
     typed-graphqlify "^2.3.0"
     yaml "^1.7.2"