diff --git a/docs/documentation/release_notes/topics/22_0_0.adoc b/docs/documentation/release_notes/topics/22_0_0.adoc
index 8523883742..1a50f6b200 100644
--- a/docs/documentation/release_notes/topics/22_0_0.adoc
+++ b/docs/documentation/release_notes/topics/22_0_0.adoc
@@ -2,6 +2,10 @@
 
 With this release, we have removed the legacy Promise API methods from the Keycloak JS adapter. This means that calling `.success()` and `.error()` on promises returned from the adapter is no longer possible.
 
+= Keycloak JS adapter must be instantiated with the `new` operator
+
+In a previous release we started to actively log deprecation warnings when the Keycloak JS adapter is constructed without the `new` operator. Starting this release doing so will throw an exception instead. This is to align with the expected behavior of https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes[JavaScript classes], which will allow further refactoring of the adapter in the future.
+
 = Export and Import perform an automatic build
 
 In previous releases, the `export` and `import` commands required a `build` command to be run first.
diff --git a/js/libs/keycloak-js/dist/keycloak.d.ts b/js/libs/keycloak-js/dist/keycloak.d.ts
index 6052af7848..075082c397 100644
--- a/js/libs/keycloak-js/dist/keycloak.d.ts
+++ b/js/libs/keycloak-js/dist/keycloak.d.ts
@@ -332,11 +332,6 @@ export interface KeycloakRoles {
  */
 export type KeycloakInstance = Keycloak;
 
-/**
- * @deprecated Construct a Keycloak instance using the `new` keyword instead.
- */
-declare function Keycloak(config?: KeycloakConfig | string): Keycloak;
-
 /**
  * A client for the Keycloak authentication server.
  * @see {@link https://keycloak.gitbooks.io/securing-client-applications-guide/content/topics/oidc/javascript-adapter.html|Keycloak JS adapter documentation}
diff --git a/js/libs/keycloak-js/src/keycloak.js b/js/libs/keycloak-js/src/keycloak.js
index 52b9e6a689..388e7541ba 100755
--- a/js/libs/keycloak-js/src/keycloak.js
+++ b/js/libs/keycloak-js/src/keycloak.js
@@ -21,19 +21,9 @@ if (typeof Promise === 'undefined') {
     throw Error('Keycloak requires an environment that supports Promises. Make sure that you include the appropriate polyfill.');
 }
 
-var loggedConstructorDeprecation = false;
-
-function logConstructorDeprecation() {
-    if (!loggedConstructorDeprecation) {
-        loggedConstructorDeprecation = true;
-        console.warn('[KEYCLOAK] Instantiation using the `Keycloak` function has been deprecated and support will be removed in future versions. Use the `new` operator to create an instance instead.');
-    }
-}
-
 function Keycloak (config) {
     if (!(this instanceof Keycloak)) {
-        logConstructorDeprecation();
-        return new Keycloak(config);
+        throw new Error("The 'Keycloak' constructor must be invoked with 'new'.")
     }
 
     var kc = this;