diff --git a/deps/cloudxr/webxr_client/helpers/BrowserCapabilities.ts b/deps/cloudxr/webxr_client/helpers/BrowserCapabilities.ts
index fc0841f91..dcffb4f73 100644
--- a/deps/cloudxr/webxr_client/helpers/BrowserCapabilities.ts
+++ b/deps/cloudxr/webxr_client/helpers/BrowserCapabilities.ts
@@ -15,6 +15,56 @@
  * limitations under the License.
  */
 
+// Minimum versions for CloudXR.js compatibility.
+// Requirements: https://docs.nvidia.com/cloudxr-sdk/latest/requirement/cloudxrjs_req.html
+// Quest OS version is not exposed in the UA; OculusBrowser 40 approximates the OS v79 era
+// (browser 41.2, Nov 2025, was the first to declare OS v81 as its minimum).
+const MIN_OCULUS_BROWSER_MAJOR = 40;
+const MIN_PICO_CHROME_MAJOR = 125;
+
+// Returns a warning message if the current browser is below the documented minimum
+// version, or null if the version is acceptable or cannot be determined.
+// Pass emulated=true when running under an XR emulator (e.g. IWER) to skip the check.
+export function checkBrowserVersion(emulated = false): string | null {
+  if (emulated) {
+    return null;
+  }
+
+  const ua = navigator.userAgent;
+
+  // Detect Pico first — Pico UAs also include "OculusBrowser/7.0" as a compat token
+  // which would otherwise match the Quest check below.
+  if (/PicoBrowser\//.test(ua)) {
+    const chromeMatch = ua.match(/Chrome\/(\d+)\./);
+    if (chromeMatch) {
+      const major = parseInt(chromeMatch[1], 10);
+      if (major < MIN_PICO_CHROME_MAJOR) {
+        return (
+          `Pico Browser (Chrome ${major}) is outdated. ` +
+          `CloudXR requires Chrome ${MIN_PICO_CHROME_MAJOR} or later. ` +
+          `Please update your headset firmware.`
+        );
+      }
+    }
+    return null;
+  }
+
+  const questMatch = ua.match(/OculusBrowser\/(\d+)\./);
+  if (questMatch) {
+    const major = parseInt(questMatch[1], 10);
+    if (major < MIN_OCULUS_BROWSER_MAJOR) {
+      return (
+        `Meta Quest Browser version ${major} detected. ` +
+        `CloudXR requires Meta Quest OS v79 or later ` +
+        `(approximately OculusBrowser ${MIN_OCULUS_BROWSER_MAJOR}+). ` +
+        `Please update your headset firmware.`
+      );
+    }
+  }
+
+  return null;
+}
+
 interface CapabilityCheck {
   name: string;
   required: boolean;
@@ -96,11 +146,40 @@ const capabilities: CapabilityCheck[] = [
         return false;
       }
     },
-    message: 'AV1 codec support is recommended for optimal streaming quality',
+    message: 'AV1 codec is not supported on this device. H.264 or HEVC can be selected as an alternative.',
+  },
+  {
+    name: 'HEVC Codec Support',
+    required: false,
+    check: async () => {
+      try {
+        if (!navigator.mediaCapabilities) {
+          return false;
+        }
+
+        const config = {
+          type: 'webrtc' as MediaDecodingType,
+          video: {
+            contentType: 'video/h265',
+            width: 1920,
+            height: 1080,
+            framerate: 60,
+            bitrate: 15000000,
+          },
+        };
+
+        const result = await navigator.mediaCapabilities.decodingInfo(config);
+        return result.supported;
+      } catch (error) {
+        console.warn('Error checking HEVC support:', error);
+        return false;
+      }
+    },
+    message: 'HEVC (H.265) codec is not supported on this device. H.264 or AV1 can be selected as an alternative.',
   },
 ];
 
-export async function checkCapabilities(): Promise<{
+export async function checkCapabilities(emulated = false): Promise<{
   success: boolean;
   failures: string[];
   warnings: string[];
@@ -109,6 +188,13 @@ export async function checkCapabilities(): Promise<{
   const warnings: string[] = [];
   const requiredFailures: string[] = [];
 
+  // Check browser version first so the warning appears at the top of the list.
+  const versionWarning = checkBrowserVersion(emulated);
+  if (versionWarning) {
+    warnings.push(versionWarning);
+    console.warn('Browser version warning:', versionWarning);
+  }
+
   for (const capability of capabilities) {
     try {
       const result = await Promise.resolve(capability.check());
diff --git a/deps/cloudxr/webxr_client/src/App.tsx b/deps/cloudxr/webxr_client/src/App.tsx
index 54c6079b9..cf61bf074 100644
--- a/deps/cloudxr/webxr_client/src/App.tsx
+++ b/deps/cloudxr/webxr_client/src/App.tsx
@@ -229,13 +229,16 @@ function App() {
       // Disable button and show checking status
       cloudXR2DUI.setStartButtonState(true, 'CONNECT (checking capabilities)');
 
+      // Set by the IWER load effect above; passed to checkCapabilities to skip browser
+      // version checks that don't apply when running under a desktop XR emulator.
+      const iwerWasLoaded = sessionStorage.getItem('iwerWasLoaded') === 'true';
       let result: { success: boolean; failures: string[]; warnings: string[] } = {
         success: false,
         failures: [],
         warnings: [],
       };
       try {
-        result = await checkCapabilities();
+        result = await checkCapabilities(iwerWasLoaded);
       } catch (error) {
         cloudXR2DUI.showStatus(`Capability check error: ${error}`, 'error');
         setCapabilitiesValid(false);
@@ -255,7 +258,6 @@ function App() {
       }
 
       // Show final status message with IWER info if applicable
-      const iwerWasLoaded = sessionStorage.getItem('iwerWasLoaded') === 'true';
       if (result.warnings.length > 0) {
         cloudXR2DUI.showStatus('Performance notice:\n' + result.warnings.join('\n'), 'info');
       } else if (iwerWasLoaded) {