diff --git a/.changeset/lucky-houses-bake.md b/.changeset/lucky-houses-bake.md
new file mode 100644
index 000000000..137a4bb60
--- /dev/null
+++ b/.changeset/lucky-houses-bake.md
@@ -0,0 +1,8 @@
+---
+'@lion/accordion': patch
+'@lion/core': patch
+'@lion/form-core': patch
+'@lion/tabs': patch
+---
+
+Fix type error, EventHandlerNonNull got removed it seems. (event: Event) => unknown; instead is fine.
diff --git a/packages/accordion/src/LionAccordion.js b/packages/accordion/src/LionAccordion.js
index 004c88aa4..85da3cd36 100644
--- a/packages/accordion/src/LionAccordion.js
+++ b/packages/accordion/src/LionAccordion.js
@@ -7,8 +7,8 @@ import { LitElement, css, html } from '@lion/core';
  * @property {number} index index of the node
  * @property {HTMLElement} invoker invoker node
  * @property {HTMLElement} content content node
- * @property {EventHandlerNonNull} clickHandler executed on click event
- * @property {EventHandlerNonNull} keydownHandler executed on keydown event
+ * @property {(event: Event) => unknown} clickHandler executed on click event
+ * @property {(event: Event) => unknown} keydownHandler executed on keydown event
  */
 
 const uuid = () => Math.random().toString(36).substr(2, 10);
diff --git a/packages/core/src/DelegateMixin.js b/packages/core/src/DelegateMixin.js
index 1fe554d0f..0a97e0292 100644
--- a/packages/core/src/DelegateMixin.js
+++ b/packages/core/src/DelegateMixin.js
@@ -8,7 +8,7 @@ import { dedupeMixin } from '@open-wc/dedupe-mixin';
 /**
  * @typedef DelegateEvent
  * @property {string} type - Type of event
- * @property {EventHandlerNonNull} handler - Event arguments
+ * @property {(event: Event) => unknown} handler - Event arguments
  * @property {boolean | AddEventListenerOptions} [opts]
  */
 
@@ -63,7 +63,7 @@ const DelegateMixinImplementation = superclass =>
 
     /**
      * @param {string} type
-     * @param {EventHandlerNonNull} handler
+     * @param {(event: Event) => unknown} handler
      * @param {boolean | AddEventListenerOptions} [opts]
      */
     addEventListener(type, handler, opts) {
diff --git a/packages/form-core/src/InteractionStateMixin.js b/packages/form-core/src/InteractionStateMixin.js
index aad91a541..314e591b6 100644
--- a/packages/form-core/src/InteractionStateMixin.js
+++ b/packages/form-core/src/InteractionStateMixin.js
@@ -104,13 +104,13 @@ const InteractionStateMixinImplementation = superclass =>
       this._valueChangedEvent = 'model-value-changed';
 
       /**
-       * @type {EventHandlerNonNull}
+       * @type {(event: Event) => unknown}
        * @protected
        */
       this._iStateOnLeave = this._iStateOnLeave.bind(this);
 
       /**
-       * @type {EventHandlerNonNull}
+       * @type {(event: Event) => unknown}
        * @protected
        */
       this._iStateOnValueChange = this._iStateOnValueChange.bind(this);
diff --git a/packages/tabs/src/LionTabs.js b/packages/tabs/src/LionTabs.js
index 6a14acfde..f2ab0309a 100644
--- a/packages/tabs/src/LionTabs.js
+++ b/packages/tabs/src/LionTabs.js
@@ -6,9 +6,9 @@ import { css, html, LitElement } from '@lion/core';
  * @property {string} uid Unique ID for the entry
  * @property {HTMLElement} button Button HTMLElement for the entry
  * @property {HTMLElement} panel Panel HTMLElement for the entry
- * @property {EventHandlerNonNull} clickHandler executed on click event
- * @property {EventHandlerNonNull} keydownHandler executed on keydown event
- * @property {EventHandlerNonNull} keyupHandler executed on keyup event
+ * @property {(event: Event) => unknown} clickHandler executed on click event
+ * @property {(event: Event) => unknown} keydownHandler executed on keydown event
+ * @property {(event: Event) => unknown} keyupHandler executed on keyup event
  */
 
 function uuid() {
@@ -237,7 +237,7 @@ export class LionTabs extends LitElement {
 
   /**
    * @param {number} index
-   * @returns {EventHandlerNonNull}
+   * @returns {(event: Event) => unknown}
    * @private
    */
   __createButtonClickHandler(index) {