Angular 4 (2017):

• Focused on reducing the framework’s size and improving performance.
• Key Features:
  • Angular Compiler: Enhancements to the Angular compiler to produce smaller code bundles.
  • Angular Forms: Improved forms handling and validation.

Angular 5 (2017):

• Key Features:
  • Angular Universal: Support for server-side rendering to improve initial load times and SEO.
  • Build Optimizer: Improved optimization for production builds.