Fails with Angular 21

[adventmedia]

Upgraded to Angular 21.
App fails to compile: "Component imports must be standalone components, directives, pipes, or must be NgModules.”

@Component({
  selector: 'app-slide-sorter',
  templateUrl: './slide-sorter.component.html',
  styleUrls: ['./slide-sorter.component.scss'],
  standalone: true,
  imports: [NgClass, FaIconComponent, SortablejsModule],
})
export class SlideSorterComponent {...

HTML:

  @for (pic of albumPics(); track pic.id) {
    <div class="sort-pic" [ngClass]="selectPicID() === pic.id ? 'selected' : ''" (click)="picSelected(pic.id)">
      <img [src]="pic.url" />
      <fa-icon class="trash-icon" [icon]="'trash-alt'" size="2x" (click)="deleteSlide(pic.id)"></fa-icon>
    </div>
  }
</div>

[Jyotibrat]

I got the same issue.