The HttpClientModule was introduced in Angular version 4.3.0. Before Angular 4.3.0, the `HttpModule` was used to handle HTTP requests and responses. However, starting from Angular 4.3.0, the `HttpModule` was deprecated in favor of the new `HttpClientModule`. The `HttpClientModule` provides a more modern and improved API for making HTTP requests and handling responses. It includes features like support for interceptors, response typing, and improved error handling. To use the `HttpClientModule`, you need to import it in your Angular module:

import { HttpClientModule } from '@angular/common/http';

@NgModule({
  imports: [
    HttpClientModule
  ],
  // ...
})
export class AppModule { }

Once imported, you can inject the `HttpClient` service into your components or services to make HTTP requests.

import { HttpClient } from '@angular/common/http';

@Injectable()
export class MyService {
  constructor(private http: HttpClient) {
  }

  getData() {
    return this.http.get('https://api.example.com/data');
  }
}

Overall, the `HttpClientModule` provides a more robust and feature-rich way to work with HTTP in Angular applications, and it has been the recommended approach since Angular 4.3.0.