diff --git a/scripts/release/create_closure_releases.ts b/scripts/release/create_closure_releases.ts
index c27d1622be..d2d616b82c 100644
--- a/scripts/release/create_closure_releases.ts
+++ b/scripts/release/create_closure_releases.ts
@@ -22,6 +22,8 @@
  * is simply invoked immediately.
  */
 
+import * as semver from 'semver';
+
 import {Change, GitClient} from './git_client';
 import {DraftReleaseOptions, GitHubClient} from './github_client';
 
@@ -247,6 +249,7 @@ export async function createClosureReleases(gitHubApiToken: string) {
   // Get the tag of the latest GitHub release.
   const from = await github.getLatestReleaseTag();
   const versionAtLastRelease = await getMajorVersionAtCommit(git, from);
+  const lastReleaseSemver = semver.coerce(versionAtLastRelease);
 
   // Get the list of commits since `from`.
   const commits = await git.listCommits({from, to: 'HEAD'});
@@ -260,6 +263,13 @@ export async function createClosureReleases(gitHubApiToken: string) {
   for (const commit of commits) {
     const version = await getMajorVersionAtCommit(git, commit.hash);
     seenCommits.push(commit);
+    if (lastReleaseSemver) {
+      const semverV = semver.coerce(version);
+      if (semverV && semver.lt(semverV, lastReleaseSemver)) {
+        // Skip versions that are older than the last version we released.
+        continue;
+      }
+    }
     if (!pJsonVersions.some((entry) => entry.version === version)) {
       pJsonVersions.push({
         version,
diff --git a/scripts/release/package-lock.json b/scripts/release/package-lock.json
index e9f05b2c5c..928986ef2d 100644
--- a/scripts/release/package-lock.json
+++ b/scripts/release/package-lock.json
@@ -9,11 +9,13 @@
       "version": "1.0.0",
       "dependencies": {
         "@octokit/rest": "^18.0.6",
+        "semver": "^7.5.4",
         "simple-git": "^3.16.0"
       },
       "devDependencies": {
         "@types/jasmine": "^3.6.0",
         "@types/node": "^14.11.2",
+        "@types/semver": "^7.5.3",
         "jasmine": "^3.6.2",
         "ts-node": "^10.9.1",
         "typescript": "^4.7.4"
@@ -314,6 +316,12 @@
       "integrity": "sha512-qzaYbXVzin6EPjghf/hTdIbnVW1ErMx8rPzwRNJhlbyJhu2SyqlvjGOY/tbUt6VFyzg56lROcOeSQRInpt63Yw==",
       "dev": true
     },
+    "node_modules/@types/semver": {
+      "version": "7.5.3",
+      "resolved": "https://registry.npmjs.org/@types/semver/-/semver-7.5.3.tgz",
+      "integrity": "sha512-OxepLK9EuNEIPxWNME+C6WwbRAOOI2o2BaQEGzz5Lu2e4Z5eDnEo+/aVEDMIXywoJitJ7xWd641wrGLZdtwRyw==",
+      "dev": true
+    },
     "node_modules/acorn": {
       "version": "8.8.0",
       "resolved": "https://registry.npmjs.org/acorn/-/acorn-8.8.0.tgz",
@@ -473,6 +481,17 @@
       "integrity": "sha512-Hu1dmuoGcZ7AfyynN3LsfruwMbxMALMka+YtZeGoLuDEySVmVAPaonkNoBRIw/ectu8b9tVQCJNgp4a4knp+tg==",
       "dev": true
     },
+    "node_modules/lru-cache": {
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-6.0.0.tgz",
+      "integrity": "sha512-Jo6dJ04CmSjuznwJSS3pUeWmd/H0ffTlkXXgwZi+eq1UCmqQwCh+eLsYOYCwY991i2Fah4h1BEMCx4qThGbsiA==",
+      "dependencies": {
+        "yallist": "^4.0.0"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/make-error": {
       "version": "1.3.6",
       "resolved": "https://registry.npmjs.org/make-error/-/make-error-1.3.6.tgz",
@@ -532,6 +551,20 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/semver": {
+      "version": "7.5.4",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.5.4.tgz",
+      "integrity": "sha512-1bCSESV6Pv+i21Hvpxp3Dx+pSD8lIPt8uVjRrxAUt/nbswYc+tK6Y2btiULjd4+fnq15PX+nqQDC7Oft7WkwcA==",
+      "dependencies": {
+        "lru-cache": "^6.0.0"
+      },
+      "bin": {
+        "semver": "bin/semver.js"
+      },
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/simple-git": {
       "version": "3.16.0",
       "resolved": "https://registry.npmjs.org/simple-git/-/simple-git-3.16.0.tgz",
@@ -637,6 +670,11 @@
       "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
       "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ=="
     },
+    "node_modules/yallist": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/yallist/-/yallist-4.0.0.tgz",
+      "integrity": "sha512-3wdGidZyq5PB084XLES5TpOSRA3wjXAlIWMhum2kRcv/41Sn2emQ0dycQW4uZXLejwKvg6EsvbdlVL+FYEct7A=="
+    },
     "node_modules/yn": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/yn/-/yn-3.1.1.tgz",
@@ -913,6 +951,12 @@
       "integrity": "sha512-qzaYbXVzin6EPjghf/hTdIbnVW1ErMx8rPzwRNJhlbyJhu2SyqlvjGOY/tbUt6VFyzg56lROcOeSQRInpt63Yw==",
       "dev": true
     },
+    "@types/semver": {
+      "version": "7.5.3",
+      "resolved": "https://registry.npmjs.org/@types/semver/-/semver-7.5.3.tgz",
+      "integrity": "sha512-OxepLK9EuNEIPxWNME+C6WwbRAOOI2o2BaQEGzz5Lu2e4Z5eDnEo+/aVEDMIXywoJitJ7xWd641wrGLZdtwRyw==",
+      "dev": true
+    },
     "acorn": {
       "version": "8.8.0",
       "resolved": "https://registry.npmjs.org/acorn/-/acorn-8.8.0.tgz",
@@ -1040,6 +1084,14 @@
       "integrity": "sha512-Hu1dmuoGcZ7AfyynN3LsfruwMbxMALMka+YtZeGoLuDEySVmVAPaonkNoBRIw/ectu8b9tVQCJNgp4a4knp+tg==",
       "dev": true
     },
+    "lru-cache": {
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-6.0.0.tgz",
+      "integrity": "sha512-Jo6dJ04CmSjuznwJSS3pUeWmd/H0ffTlkXXgwZi+eq1UCmqQwCh+eLsYOYCwY991i2Fah4h1BEMCx4qThGbsiA==",
+      "requires": {
+        "yallist": "^4.0.0"
+      }
+    },
     "make-error": {
       "version": "1.3.6",
       "resolved": "https://registry.npmjs.org/make-error/-/make-error-1.3.6.tgz",
@@ -1082,6 +1134,14 @@
       "integrity": "sha512-AVbw3UJ2e9bq64vSaS9Am0fje1Pa8pbGqTTsmXfaIiMpnr5DlDhfJOuLj9Sf95ZPVDAUerDfEk88MPmPe7UCQg==",
       "dev": true
     },
+    "semver": {
+      "version": "7.5.4",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.5.4.tgz",
+      "integrity": "sha512-1bCSESV6Pv+i21Hvpxp3Dx+pSD8lIPt8uVjRrxAUt/nbswYc+tK6Y2btiULjd4+fnq15PX+nqQDC7Oft7WkwcA==",
+      "requires": {
+        "lru-cache": "^6.0.0"
+      }
+    },
     "simple-git": {
       "version": "3.16.0",
       "resolved": "https://registry.npmjs.org/simple-git/-/simple-git-3.16.0.tgz",
@@ -1154,6 +1214,11 @@
       "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
       "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ=="
     },
+    "yallist": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/yallist/-/yallist-4.0.0.tgz",
+      "integrity": "sha512-3wdGidZyq5PB084XLES5TpOSRA3wjXAlIWMhum2kRcv/41Sn2emQ0dycQW4uZXLejwKvg6EsvbdlVL+FYEct7A=="
+    },
     "yn": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/yn/-/yn-3.1.1.tgz",
diff --git a/scripts/release/package.json b/scripts/release/package.json
index 5b326d85f7..692c059f72 100644
--- a/scripts/release/package.json
+++ b/scripts/release/package.json
@@ -4,15 +4,18 @@
   "version": "1.0.0",
   "scripts": {
     "start": "ts-node create_closure_releases",
+    "debug": "node --inspect --inspect-brk -r ts-node/register create_closure_releases.ts",
     "test": "ts-node $(npm bin)/jasmine *_test.ts"
   },
   "dependencies": {
     "@octokit/rest": "^18.0.6",
+    "semver": "^7.5.4",
     "simple-git": "^3.16.0"
   },
   "devDependencies": {
     "@types/jasmine": "^3.6.0",
     "@types/node": "^14.11.2",
+    "@types/semver": "^7.5.3",
     "jasmine": "^3.6.2",
     "ts-node": "^10.9.1",
     "typescript": "^4.7.4"