diff --git a/.changeset/smooth-foxes-jump.md b/.changeset/smooth-foxes-jump.md
new file mode 100644
index 00000000000..7eea6259fc6
--- /dev/null
+++ b/.changeset/smooth-foxes-jump.md
@@ -0,0 +1,6 @@
+---
+'@clerk/upgrade': patch
+---
+
+Handle `catalog:` protocol and other non-standard version specifiers
+
diff --git a/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/package.json b/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/package.json
new file mode 100644
index 00000000000..24f7253f2b9
--- /dev/null
+++ b/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/package.json
@@ -0,0 +1,9 @@
+{
+  "name": "test-nextjs-catalog",
+  "version": "1.0.0",
+  "dependencies": {
+    "@clerk/nextjs": "catalog:",
+    "next": "^14.0.0",
+    "react": "^18.0.0"
+  }
+}
diff --git a/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/pnpm-lock.yaml b/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/pnpm-lock.yaml
new file mode 100644
index 00000000000..876cf5cca99
--- /dev/null
+++ b/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/pnpm-lock.yaml
@@ -0,0 +1,5 @@
+lockfileVersion: '9.0'
+settings:
+  autoInstallPeers: true
+  excludeLinksFromLockfile: false
+
diff --git a/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/src/app.tsx b/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/src/app.tsx
new file mode 100644
index 00000000000..df659a20472
--- /dev/null
+++ b/packages/upgrade/src/__tests__/fixtures/nextjs-catalog/src/app.tsx
@@ -0,0 +1,5 @@
+import { SignIn } from '@clerk/nextjs';
+
+export default function Home() {
+  return <SignIn />;
+}
diff --git a/packages/upgrade/src/__tests__/integration/config.test.js b/packages/upgrade/src/__tests__/integration/config.test.js
index 79a56976f2c..21c46f9a594 100644
--- a/packages/upgrade/src/__tests__/integration/config.test.js
+++ b/packages/upgrade/src/__tests__/integration/config.test.js
@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest';
 
-import { getOldPackageName, getTargetPackageName, loadConfig } from '../../config.js';
+import { getAvailableReleases, getOldPackageName, getTargetPackageName, loadConfig } from '../../config.js';
 
 describe('loadConfig', () => {
   it('returns config with needsUpgrade: true for nextjs v6', async () => {
@@ -128,3 +128,46 @@ describe('getOldPackageName', () => {
     expect(getOldPackageName('nextjs')).toBeNull();
   });
 });
+
+describe('getAvailableReleases', () => {
+  it('returns an array of available releases', () => {
+    const releases = getAvailableReleases();
+
+    expect(Array.isArray(releases)).toBe(true);
+    expect(releases.length).toBeGreaterThan(0);
+  });
+
+  it('includes core-3 release', () => {
+    const releases = getAvailableReleases();
+
+    expect(releases).toContain('core-3');
+  });
+
+  it('includes core-2 release', () => {
+    const releases = getAvailableReleases();
+
+    expect(releases).toContain('core-2');
+  });
+
+  it('returns releases in reverse order (newest first)', () => {
+    const releases = getAvailableReleases();
+
+    expect(releases[0]).toBe('core-3');
+    expect(releases[1]).toBe('core-2');
+  });
+});
+
+describe('loadConfig with null version', () => {
+  it('returns config when release is explicitly provided', async () => {
+    const config = await loadConfig('nextjs', null, 'core-3');
+
+    expect(config).not.toBeNull();
+    expect(config.id).toBe('core-3');
+  });
+
+  it('returns null when no release is provided and version is null', async () => {
+    const config = await loadConfig('nextjs', null);
+
+    expect(config).toBeNull();
+  });
+});
diff --git a/packages/upgrade/src/__tests__/integration/detect-sdk.test.js b/packages/upgrade/src/__tests__/integration/detect-sdk.test.js
index 28543456dbe..356606ef9ee 100644
--- a/packages/upgrade/src/__tests__/integration/detect-sdk.test.js
+++ b/packages/upgrade/src/__tests__/integration/detect-sdk.test.js
@@ -56,6 +56,11 @@ describe('getSdkVersion', () => {
     const version = getSdkVersion('nextjs', getFixturePath('no-clerk'));
     expect(version).toBeNull();
   });
+
+  it('returns null for catalog: protocol versions', () => {
+    const version = getSdkVersion('nextjs', getFixturePath('nextjs-catalog'));
+    expect(version).toBeNull();
+  });
 });
 
 describe('getMajorVersion', () => {
@@ -78,6 +83,18 @@ describe('getMajorVersion', () => {
   it('returns null for invalid semver', () => {
     expect(getMajorVersion('invalid')).toBeNull();
   });
+
+  it('returns null for catalog: protocol', () => {
+    expect(getMajorVersion('catalog:')).toBeNull();
+  });
+
+  it('returns null for catalog:default', () => {
+    expect(getMajorVersion('catalog:default')).toBeNull();
+  });
+
+  it('returns null for workspace: protocol', () => {
+    expect(getMajorVersion('workspace:*')).toBeNull();
+  });
 });
 
 describe('normalizeSdkName', () => {
diff --git a/packages/upgrade/src/cli.js b/packages/upgrade/src/cli.js
index 54eb7deef7f..55e6121642c 100644
--- a/packages/upgrade/src/cli.js
+++ b/packages/upgrade/src/cli.js
@@ -1,7 +1,7 @@
 #!/usr/bin/env node
 import meow from 'meow';
 
-import { getOldPackageName, getTargetPackageName, loadConfig } from './config.js';
+import { getAvailableReleases, getOldPackageName, getTargetPackageName, loadConfig } from './config.js';
 import {
   createSpinner,
   promptConfirm,
@@ -119,15 +119,52 @@ async function main() {
   const currentVersion = getSdkVersion(sdk, options.dir);
   const packageManager = detectPackageManager(options.dir);
 
-  // Step 3: Load version config
-  const config = await loadConfig(sdk, currentVersion, options.release);
+  // Step 3: If version couldn't be detected and no release specified, prompt user
+  let release = options.release;
+
+  if (currentVersion === null && !release) {
+    const availableReleases = getAvailableReleases();
+
+    if (availableReleases.length === 0) {
+      renderError('No upgrade configurations found.');
+      process.exit(1);
+    }
+
+    renderWarning(
+      `Could not detect your @clerk/${sdk} version (you may be using catalog: protocol or a non-standard version specifier).`,
+    );
+    renderNewline();
+
+    if (!isInteractive) {
+      renderError('Please provide --release flag in non-interactive mode.');
+      renderText('Available releases: ' + availableReleases.join(', '));
+      process.exit(1);
+    }
+
+    const releaseOptions = availableReleases.map(r => ({
+      label: r.replace('-', ' ').replace(/\b\w/g, c => c.toUpperCase()),
+      value: r,
+    }));
+
+    release = await promptSelect('Which upgrade would you like to perform?', releaseOptions);
+
+    if (!release) {
+      renderError('No release selected. Exiting.');
+      process.exit(1);
+    }
+
+    renderNewline();
+  }
+
+  // Step 4: Load version config
+  const config = await loadConfig(sdk, currentVersion, release);
 
   if (!config) {
     renderError(`No upgrade path found for @clerk/${sdk}. Your version may be too old for this upgrade tool.`);
     process.exit(1);
   }
 
-  // Step 4: Display configuration
+  // Step 5: Display configuration
   renderConfig({
     sdk,
     currentVersion,
@@ -145,7 +182,7 @@ async function main() {
 
   console.log('');
 
-  // Step 5: Handle upgrade status
+  // Step 6: Handle upgrade status
   if (options.skipUpgrade) {
     renderText('Skipping package upgrade (--skip-upgrade flag)', 'yellow');
     renderNewline();
@@ -155,7 +192,7 @@ async function main() {
     await performUpgrade(sdk, packageManager, config, options);
   }
 
-  // Step 6: Run codemods
+  // Step 7: Run codemods
   if (config.codemods?.length > 0) {
     renderText(`Running ${config.codemods.length} codemod(s)...`, 'blue');
     await runCodemods(config, sdk, options);
@@ -163,14 +200,14 @@ async function main() {
     renderNewline();
   }
 
-  // Step 7: Run scans
+  // Step 8: Run scans
   if (config.changes?.length > 0) {
     renderText('Scanning for additional breaking changes...', 'blue');
     const results = await runScans(config, sdk, options);
     renderScanResults(results, config.docsUrl);
   }
 
-  // Step 8: Done
+  // Step 9: Done
   renderComplete(sdk, config.docsUrl);
 }
 
diff --git a/packages/upgrade/src/config.js b/packages/upgrade/src/config.js
index 3316b03d400..00abfad009c 100644
--- a/packages/upgrade/src/config.js
+++ b/packages/upgrade/src/config.js
@@ -7,6 +7,16 @@ import matter from 'gray-matter';
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const VERSIONS_DIR = path.join(__dirname, 'versions');
 
+export function getAvailableReleases() {
+  return fs
+    .readdirSync(VERSIONS_DIR, { withFileTypes: true })
+    .filter(d => d.isDirectory())
+    .map(d => d.name)
+    .filter(name => fs.existsSync(path.join(VERSIONS_DIR, name, 'index.js')))
+    .sort()
+    .reverse();
+}
+
 export async function loadConfig(sdk, currentVersion, release) {
   const versionDirs = fs
     .readdirSync(VERSIONS_DIR, { withFileTypes: true })