diff --git a/packages/angular/testing/src/testing-utils.ts b/packages/angular/testing/src/testing-utils.ts
index 1b007bab72..303fc0a0fc 100644
--- a/packages/angular/testing/src/testing-utils.ts
+++ b/packages/angular/testing/src/testing-utils.ts
@@ -2,6 +2,8 @@ import type { Observable } from 'rxjs';
 import { first, toArray } from 'rxjs/operators';
 
 /**
+ * @deprecated This will be removed in a later version of Nx. Since RxJS 7, use firstValueFrom(obs$.pipe(toArray())) or lastValueFrom(obs$.pipe(toArray())).
+ *
  * @whatItDoes reads all the values from an observable and returns a promise
  * with an array of all values. This should be used in combination with async/await.
  *
@@ -18,6 +20,8 @@ export function readAll<T>(o: Observable<T>): Promise<T[]> {
 }
 
 /**
+ * @deprecated This will be removed in a later version of Nx. Since RxJS 7, use firstValueFrom(obs$)
+ *
  * @whatItDoes reads the first value from an observable and returns a promise
  * with it. This should be used in combination with async/await.
  *