# Next.js 16 Upgrade Guide

## Current Status
- **Current Version**: Next.js 15.2.6
- **Target Version**: Next.js 16.1.1
- **React Version**: 19.0.0 ✅ (Compatible)

## Upgrade Steps

### 1. Backup First
```bash
git add .
git commit -m "Before Next.js 16 upgrade"
```

### 2. Update Dependencies
```bash
npm install next@16 react@19 react-dom@19 eslint-config-next@16
```

### 3. Update Related Packages
```bash
npm install @next/bundle-analyzer@latest
```

### 4. Test Build
```bash
npm run build
```

### 5. Test Development Server
```bash
npm run dev
```

## Potential Breaking Changes

### 1. Route Handlers
- Check all API routes in `app/api/` for compatibility
- Ensure async/await patterns are correct

### 2. Server Components
- Verify all server components work correctly
- Check for any client component boundaries

### 3. Image Optimization
- `next/image` may have minor API changes
- Check image imports

### 4. Font Loading
- `next/font` should work the same, but verify

## Performance Improvements Expected

1. **Faster Builds**: 10-20% faster production builds
2. **Better Caching**: Improved static generation caching
3. **Smaller Bundles**: Better tree-shaking and code splitting
4. **Faster Dev Server**: Turbopack improvements

## Rollback Plan

If issues occur:
```bash
npm install next@15.2.6 react@19 react-dom@19 eslint-config-next@15.2.3
```

## Testing Checklist

- [ ] Build completes successfully
- [ ] Dev server starts without errors
- [ ] All pages load correctly
- [ ] API routes work
- [ ] Images load properly
- [ ] Fonts load correctly
- [ ] Admin dashboard works
- [ ] Order management works
- [ ] Analytics charts render
- [ ] Authentication works