diff --git a/Mac/AppDefaults.swift b/Mac/AppDefaults.swift
index 9d9d9f884..278a53525 100644
--- a/Mac/AppDefaults.swift
+++ b/Mac/AppDefaults.swift
@@ -14,7 +14,7 @@ enum FontSize: Int {
 	case veryLarge = 3
 }
 
-struct AppDefaults {
+final class AppDefaults {
 	
 	static var shared = AppDefaults()
 	private init() {}
diff --git a/iOS/AppDefaults.swift b/iOS/AppDefaults.swift
index 9f6c757f4..a9ad904d0 100644
--- a/iOS/AppDefaults.swift
+++ b/iOS/AppDefaults.swift
@@ -26,7 +26,7 @@ enum UserInterfaceColorPalette: Int, CustomStringConvertible, CaseIterable {
 	
 }
 
-class AppDefaults {
+final class AppDefaults {
 
 	static let shared = AppDefaults()
 	private init() {}