diff --git a/src/cliproxy/binary-manager.ts b/src/cliproxy/binary-manager.ts
index 51a33d45..7e52e81a 100644
--- a/src/cliproxy/binary-manager.ts
+++ b/src/cliproxy/binary-manager.ts
@@ -8,7 +8,7 @@
 import { info, warn } from '../utils/ui';
 import { getBinDir, CLIPROXY_DEFAULT_PORT } from './config-generator';
 import { BinaryInfo, BinaryManagerConfig } from './types';
-import { CLIPROXY_FALLBACK_VERSION } from './platform-detector';
+import { CLIPROXY_FALLBACK_VERSION, CLIPROXY_MAX_STABLE_VERSION } from './platform-detector';
 import { isProxyRunning, stopProxy } from './services/proxy-lifecycle-service';
 import { waitForPortFree } from '../utils/port-utils';
 import {
@@ -151,11 +151,29 @@ export interface CliproxyUpdateCheckResult {
   latestVersion: string;
   fromCache: boolean;
   checkedAt: number;
+  // Stability fields
+  isStable: boolean;
+  maxStableVersion: string;
+  stabilityMessage?: string;
 }
 
 /** Check for CLIProxyAPI binary updates */
 export async function checkCliproxyUpdate(): Promise<CliproxyUpdateCheckResult> {
-  return new BinaryManager().checkForUpdates();
+  const result = await new BinaryManager().checkForUpdates();
+
+  // Import isNewerVersion for stability check
+  const { isNewerVersion } = await import('./binary/version-checker');
+  const isStable = !isNewerVersion(result.currentVersion, CLIPROXY_MAX_STABLE_VERSION);
+  const stabilityMessage = isStable
+    ? undefined
+    : `v${result.currentVersion} has known stability issues. Max stable: v${CLIPROXY_MAX_STABLE_VERSION}`;
+
+  return {
+    ...result,
+    isStable,
+    maxStableVersion: CLIPROXY_MAX_STABLE_VERSION,
+    stabilityMessage,
+  };
 }
 
 // Re-export version pin functions
diff --git a/src/web-server/health/cliproxy-checks.ts b/src/web-server/health/cliproxy-checks.ts
index 5c1ee2f1..fb41c7af 100644
--- a/src/web-server/health/cliproxy-checks.ts
+++ b/src/web-server/health/cliproxy-checks.ts
@@ -15,6 +15,8 @@ import {
 } from '../../cliproxy';
 import { getPortProcess, isCLIProxyProcess } from '../../utils/port-utils';
 import type { HealthCheck } from './types';
+import { CLIPROXY_MAX_STABLE_VERSION } from '../../cliproxy/platform-detector';
+import { isNewerVersion } from '../../cliproxy/binary/version-checker';
 
 /**
  * Check CLIProxy binary installation
@@ -23,6 +25,21 @@ export function checkCliproxyBinary(): HealthCheck {
   if (isCLIProxyInstalled()) {
     const version = getInstalledCliproxyVersion();
     const binaryPath = getCLIProxyPath();
+
+    // Check if version exceeds stable cap
+    const isUnstable = isNewerVersion(version, CLIPROXY_MAX_STABLE_VERSION);
+
+    if (isUnstable) {
+      return {
+        id: 'cliproxy-binary',
+        name: 'CLIProxy Binary',
+        status: 'warning',
+        message: `v${version} (unstable)`,
+        details: binaryPath,
+        fix: `Downgrade: ccs cliproxy install ${CLIPROXY_MAX_STABLE_VERSION.replace(/-\d+$/, '')}`,
+      };
+    }
+
     return {
       id: 'cliproxy-binary',
       name: 'CLIProxy Binary',
diff --git a/ui/src/components/cliproxy/cliproxy-header.tsx b/ui/src/components/cliproxy/cliproxy-header.tsx
index a2d39178..956d37ca 100644
--- a/ui/src/components/cliproxy/cliproxy-header.tsx
+++ b/ui/src/components/cliproxy/cliproxy-header.tsx
@@ -6,11 +6,17 @@
 import { useState, useEffect } from 'react';
 import { Button } from '@/components/ui/button';
 import { Badge } from '@/components/ui/badge';
-import { RefreshCw, Loader2 } from 'lucide-react';
+import { RefreshCw, Loader2, AlertTriangle } from 'lucide-react';
 import { useCliproxyAuth } from '@/hooks/use-cliproxy';
 import { useCliproxyAuthFlow } from '@/hooks/use-cliproxy-auth-flow';
 import { cn } from '@/lib/utils';
 
+interface VersionInfo {
+  currentVersion: string;
+  isStable: boolean;
+  stabilityMessage?: string;
+}
+
 interface LoginButtonProps {
   provider: string;
   displayName: string;
@@ -110,6 +116,22 @@ export function CliproxyHeader({
   const { data: authData } = useCliproxyAuth();
   const { provider: authProvider, isAuthenticating, startAuth } = useCliproxyAuthFlow();
   const lastUpdatedText = useRelativeTime(lastUpdated);
+  const [versionInfo, setVersionInfo] = useState<VersionInfo | null>(null);
+
+  useEffect(() => {
+    fetch('/api/cliproxy/update-check')
+      .then((res) => (res.ok ? res.json() : null))
+      .then((data) => {
+        if (data) {
+          setVersionInfo({
+            currentVersion: data.currentVersion,
+            isStable: data.isStable,
+            stabilityMessage: data.stabilityMessage,
+          });
+        }
+      })
+      .catch(() => {}); // Silently fail
+  }, []);
 
   const providers = [
     { id: 'claude', displayName: 'Claude' },
@@ -170,6 +192,21 @@ export function CliproxyHeader({
           {isRunning ? 'Running' : 'Offline'}
         </Badge>
 
+        {versionInfo && (
+          <Badge
+            variant={versionInfo.isStable ? 'secondary' : 'destructive'}
+            className={cn(
+              'gap-1.5',
+              !versionInfo.isStable &&
+                'bg-amber-500/20 text-amber-600 dark:text-amber-400 border-amber-500/30'
+            )}
+            title={versionInfo.stabilityMessage}
+          >
+            {!versionInfo.isStable && <AlertTriangle className="w-3 h-3" />}v
+            {versionInfo.currentVersion}
+          </Badge>
+        )}
+
         {lastUpdatedText && (
           <span className="text-xs text-muted-foreground">{lastUpdatedText}</span>
         )}