diff --git a/backend/extension-src/README.md b/backend/extension-src/README.md
index 75aa05c..26d3e85 100644
--- a/backend/extension-src/README.md
+++ b/backend/extension-src/README.md
@@ -46,6 +46,15 @@ running the [`tablet-checkin`](../tablet-checkin) app.
 4. Click the extension icon → **Open Settings** (or right-click the icon → Options) →
    enter the tablet-checkin base URL and the terminal key → Save → Test connection.
 
+## Versioning
+
+Bump `manifest.json`'s `"version"` field every time anything in this folder changes.
+Nothing does this automatically. The popup shows its own installed version in a small
+footer; tablet-checkin's Terminals page shows the latest bundled version next to the
+download link (`GET /api/extension/version`, reads this same file) — that comparison is
+how staff tell an already-installed copy on a reception PC is stale and needs
+re-downloading, so a missed bump silently breaks that signal.
+
 ## Known TODOs before this is production-ready
 
 - **Row-detection selectors on `bookings_lists_checkin` are built from a single sample
diff --git a/backend/extension-src/manifest.json b/backend/extension-src/manifest.json
index 2ca4eca..3a9c3d1 100644
--- a/backend/extension-src/manifest.json
+++ b/backend/extension-src/manifest.json
@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "Send to Check-In Tablet",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "description": "Pushes the currently open NewBook booking to a check-in tablet — standalone from NewBook Assistant, see project_checkin memory.",
 
   "permissions": ["cookies", "storage", "activeTab", "webNavigation"],
diff --git a/backend/extension-src/popup/popup.css b/backend/extension-src/popup/popup.css
index 860f358..4f3f82a 100644
--- a/backend/extension-src/popup/popup.css
+++ b/backend/extension-src/popup/popup.css
@@ -97,3 +97,7 @@ a.settings-link { display: block; margin-top: 12px; font-size: 12px; color: #7b4
   padding: 4px 10px; border-radius: 6px; cursor: pointer;
 }
 .send-small:disabled { opacity: 0.5; cursor: default; }
+
+.version {
+  margin-top: 10px; text-align: center; font-size: 10px; color: #94a3b8;
+}
diff --git a/backend/extension-src/popup/popup.html b/backend/extension-src/popup/popup.html
index ec0b483..5d98889 100644
--- a/backend/extension-src/popup/popup.html
+++ b/backend/extension-src/popup/popup.html
@@ -15,6 +15,8 @@
     <p class="muted">Loading…</p>
   </div>
 
+  <div id="version" class="version"></div>
+
   <script type="module" src="popup.js"></script>
 </body>
 </html>
diff --git a/backend/extension-src/popup/popup.js b/backend/extension-src/popup/popup.js
index 3e9ecda..a7d0ae5 100644
--- a/backend/extension-src/popup/popup.js
+++ b/backend/extension-src/popup/popup.js
@@ -9,6 +9,15 @@ const BOOKING_URL_RE = /\/bookings_(?:view|edit|checkin)\/(\d+)/i;
 
 const contentEl = document.getElementById('content');
 const nbStatusEl = document.getElementById('nbStatus');
+const versionEl = document.getElementById('version');
+
+// Shown so staff/admin can tell at a glance whether a given reception PC is
+// running an old install — compare against the "Latest version" shown next
+// to the download link on tablet-checkin's own Terminals page (see
+// routes/extension.js's /api/extension/version). Pulled from the manifest
+// rather than hardcoded here, so it can never itself drift out of sync with
+// manifest.json's own version field.
+versionEl.textContent = `v${chrome.runtime.getManifest().version}`;
 
 async function main() {
   const [tab] = await chrome.tabs.query({ active: true, currentWindow: true });
diff --git a/backend/src/routes/extension.js b/backend/src/routes/extension.js
index edd80cf..0e9cdae 100644
--- a/backend/src/routes/extension.js
+++ b/backend/src/routes/extension.js
@@ -1,4 +1,5 @@
 import path from 'path'
+import { readFileSync } from 'fs'
 import { fileURLToPath } from 'url'
 import archiver from 'archiver'
 import { requireAuth, requireCap } from '../auth.js'
@@ -14,6 +15,19 @@ const __dirname = path.dirname(fileURLToPath(import.meta.url))
 const EXTENSION_SRC = path.join(__dirname, '..', '..', 'extension-src')
 
 export async function extensionRoutes(app) {
+  // GET /api/extension/version — read straight from manifest.json rather than
+  // a separately-maintained value, so this can never itself drift out of sync
+  // with what the download link actually serves. Shown next to that link on
+  // the Terminals page so staff can tell an already-installed copy (its own
+  // version shown in the extension's popup footer) is behind the latest
+  // bundled one and should be re-downloaded. Bump manifest.json's "version"
+  // field on every change to backend/extension-src/ — nothing else does this
+  // automatically.
+  app.get('/api/extension/version', { preHandler: [requireAuth, requireCap('settings')] }, async () => {
+    const manifest = JSON.parse(readFileSync(path.join(EXTENSION_SRC, 'manifest.json'), 'utf8'))
+    return { version: manifest.version }
+  })
+
   // Gated the same as the Settings page it's linked from — any staff who can
   // see Settings can download this, nothing sensitive lives in the extension
   // itself (the terminal API key is entered by whoever installs it, not
diff --git a/frontend/src/api.ts b/frontend/src/api.ts
index d9f3c4e..3bf51a9 100644
--- a/frontend/src/api.ts
+++ b/frontend/src/api.ts
@@ -58,6 +58,7 @@ export function checkinPdfUrl(id: number): string { return `${BASE}/checkins/${i
 // backend/extension-src), zipped fresh on each request rather than served as
 // a static file. See project_checkin memory's "Standalone push extension".
 export function extensionDownloadUrl(): string { return `${BASE}/extension/download` }
+export function fetchExtensionVersion(): Promise<{ version: string }> { return request('/extension/version') }
 
 // Marketing
 export function fetchMarketingProviders(): Promise<MarketingProvider[]> { return request('/marketing/providers') }
diff --git a/frontend/src/pages/Terminals.tsx b/frontend/src/pages/Terminals.tsx
index 04abba5..295c4ab 100644
--- a/frontend/src/pages/Terminals.tsx
+++ b/frontend/src/pages/Terminals.tsx
@@ -1,6 +1,6 @@
 import { useEffect, useState } from 'react'
 import { RefreshCw, KeyRound, Ban, Trash2, Copy, Download } from 'lucide-react'
-import { fetchTerminals, createTerminal, revokeTerminal, deleteTerminal, extensionDownloadUrl } from '../api'
+import { fetchTerminals, createTerminal, revokeTerminal, deleteTerminal, extensionDownloadUrl, fetchExtensionVersion } from '../api'
 import type { Terminal } from '../types'
 
 export default function Terminals() {
@@ -10,6 +10,7 @@ export default function Terminals() {
   const [newName, setNewName] = useState('')
   const [creating, setCreating] = useState(false)
   const [revealedKey, setRevealedKey] = useState<{ name: string; key: string } | null>(null)
+  const [extensionVersion, setExtensionVersion] = useState('')
 
   function load() {
     setLoading(true)
@@ -20,6 +21,7 @@ export default function Terminals() {
   }
 
   useEffect(load, [])
+  useEffect(() => { fetchExtensionVersion().then(v => setExtensionVersion(v.version)).catch(() => {}) }, [])
 
   async function handleCreate(e: React.FormEvent) {
     e.preventDefault()
@@ -77,9 +79,12 @@ export default function Terminals() {
           select the unzipped folder. It'll need a terminal key from below to actually authorize
           pushes — create one first if you haven't already.
         </p>
-        <a className="btn" href={extensionDownloadUrl()} style={{ display: 'inline-flex', alignItems: 'center', gap: 6, textDecoration: 'none' }}>
-          <Download size={16} strokeWidth={1.75} /> Download Extension (.zip)
-        </a>
+        <div style={{ display: 'flex', alignItems: 'center', gap: 10 }}>
+          <a className="btn" href={extensionDownloadUrl()} style={{ display: 'inline-flex', alignItems: 'center', gap: 6, textDecoration: 'none' }}>
+            <Download size={16} strokeWidth={1.75} /> Download Extension (.zip)
+          </a>
+          {extensionVersion && <span className="field-hint">Latest version: {extensionVersion}</span>}
+        </div>
       </div>
 
       {error && <div className="error-banner">{error}</div>}