diff --git a/UITextField-Navigation/Classes/NavigationFieldToolbar.swift b/UITextField-Navigation/Classes/NavigationFieldToolbar.swift
index f60ba86..ae98fb0 100644
--- a/UITextField-Navigation/Classes/NavigationFieldToolbar.swift
+++ b/UITextField-Navigation/Classes/NavigationFieldToolbar.swift
@@ -8,7 +8,7 @@
 
 import UIKit
 
-protocol NavigationFieldToolbarDelegate: class {
+protocol NavigationFieldToolbarDelegate: AnyObject {
 
     func navigationFieldToolbarDidTapPreviousButton(_ navigationFieldToolbar: NavigationFieldToolbar)
     func navigationFieldToolbarDidTapNextButton(_ navigationFieldToolbar: NavigationFieldToolbar)