diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6a245ce8..dbbeea73 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -44,6 +44,16 @@
 - Removed `URLProtectionSpace.iosIsProxy` property
 - `historyUrl` and `baseUrl` of `InAppWebViewInitialData` can be `null`
 
+## 5.5.0+3
+
+- Fixed iOS `toolbarTopTintColor` InAppBrowser option
+- Fixed iOS `InAppBrowserOptions.hideProgressBar` when getting options
+- Fixed missing implementation `InAppBrowser.isHidden` method on Android and iOS
+- Fixed "Attempt to invoke virtual method 'java.lang.String android.webkit.WebView.getUrl()' on a null object reference" [#1324](https://github.com/pichillilorenzo/flutter_inappwebview/issues/1324)
+- Fixed "(Crash) NullPointerException at in_app_browser.InAppBrowserActivity.close' on a null object reference" [#1278](https://github.com/pichillilorenzo/flutter_inappwebview/issues/1278)
+- Fixed "ios system version parser error" [#1355](https://github.com/pichillilorenzo/flutter_inappwebview/issues/1355)
+- Removed unnamed constructors for all Singleton classes to avoid incorrect usage
+
 ## 5.5.0+2
 
 - Fixed README
diff --git a/ios/Classes/InAppBrowser/InAppBrowserSettings.swift b/ios/Classes/InAppBrowser/InAppBrowserSettings.swift
index 1449b312..384acb4f 100755
--- a/ios/Classes/InAppBrowser/InAppBrowserSettings.swift
+++ b/ios/Classes/InAppBrowser/InAppBrowserSettings.swift
@@ -37,7 +37,7 @@ public class InAppBrowserSettings: ISettings<InAppBrowserWebViewController> {
         if let inAppBrowserWebViewController = obj {
             realOptions["hidden"] = inAppBrowserWebViewController.isHidden
             realOptions["hideUrlBar"] = inAppBrowserWebViewController.searchBar.isHidden
-            realOptions["progressBar"] = inAppBrowserWebViewController.progressBar.isHidden
+            realOptions["hideProgressBar"] = inAppBrowserWebViewController.progressBar.isHidden
             realOptions["closeButtonCaption"] = inAppBrowserWebViewController.closeButton.title
             realOptions["closeButtonColor"] = inAppBrowserWebViewController.closeButton.tintColor?.hexString
             if let navController = inAppBrowserWebViewController.navigationController {
diff --git a/lib/src/android/proxy_controller.dart b/lib/src/android/proxy_controller.dart
index ce0f438a..50d3210a 100644
--- a/lib/src/android/proxy_controller.dart
+++ b/lib/src/android/proxy_controller.dart
@@ -19,6 +19,8 @@ class ProxyController {
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_proxycontroller');
 
+  ProxyController._();
+
   ///Gets the [ProxyController] shared instance.
   ///
   ///This method should only be called if [WebViewFeature.isFeatureSupported] returns `true` for [WebViewFeature.PROXY_OVERRIDE].
@@ -35,7 +37,7 @@ class ProxyController {
         print(e.stackTrace);
       }
     });
-    _instance = ProxyController();
+    _instance = ProxyController._();
     return _instance!;
   }
 
diff --git a/lib/src/android/service_worker_controller.dart b/lib/src/android/service_worker_controller.dart
index 7b8cb042..8f180332 100644
--- a/lib/src/android/service_worker_controller.dart
+++ b/lib/src/android/service_worker_controller.dart
@@ -15,6 +15,8 @@ class ServiceWorkerController {
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_serviceworkercontroller');
 
+  ServiceWorkerController._();
+
   ///Gets the [ServiceWorkerController] shared instance.
   ///
   ///This method should only be called if [WebViewFeature.isFeatureSupported] returns `true` for [WebViewFeature.SERVICE_WORKER_BASIC_USAGE].
@@ -47,7 +49,7 @@ class ServiceWorkerController {
         print(e.stackTrace);
       }
     });
-    _instance = ServiceWorkerController();
+    _instance = ServiceWorkerController._();
     return _instance!;
   }
 
diff --git a/lib/src/cookie_manager.dart b/lib/src/cookie_manager.dart
index a97b017f..5d85d608 100755
--- a/lib/src/cookie_manager.dart
+++ b/lib/src/cookie_manager.dart
@@ -27,6 +27,8 @@ class CookieManager {
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_cookiemanager');
 
+  CookieManager._();
+
   ///Use [CookieManager] instead.
   @Deprecated("Use CookieManager instead")
   late IOSCookieManager ios;
@@ -45,7 +47,7 @@ class CookieManager {
         print(e.stackTrace);
       }
     });
-    _instance = CookieManager();
+    _instance = CookieManager._();
     // ignore: deprecated_member_use_from_same_package
     _instance!.ios = IOSCookieManager.instance();
     return _instance!;
@@ -542,8 +544,10 @@ class IOSCookieManager {
     return (_instance != null) ? _instance! : _init();
   }
 
+  IOSCookieManager._();
+
   static IOSCookieManager _init() {
-    _instance = IOSCookieManager();
+    _instance = IOSCookieManager._();
     return _instance!;
   }
 
diff --git a/lib/src/http_auth_credentials_database.dart b/lib/src/http_auth_credentials_database.dart
index 53027398..8baa1368 100755
--- a/lib/src/http_auth_credentials_database.dart
+++ b/lib/src/http_auth_credentials_database.dart
@@ -18,6 +18,8 @@ class HttpAuthCredentialDatabase {
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_credential_database');
 
+  HttpAuthCredentialDatabase._();
+
   ///Gets the database shared instance.
   static HttpAuthCredentialDatabase instance() {
     return (_instance != null) ? _instance! : _init();
@@ -32,7 +34,7 @@ class HttpAuthCredentialDatabase {
         print(e.stackTrace);
       }
     });
-    _instance = HttpAuthCredentialDatabase();
+    _instance = HttpAuthCredentialDatabase._();
     return _instance!;
   }
 
diff --git a/lib/src/platform_util.dart b/lib/src/platform_util.dart
index c93d9761..71250cb8 100644
--- a/lib/src/platform_util.dart
+++ b/lib/src/platform_util.dart
@@ -6,6 +6,8 @@ class PlatformUtil {
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_platformutil');
 
+  PlatformUtil._();
+
   ///Get [PlatformUtil] instance.
   static PlatformUtil instance() {
     return (_instance != null) ? _instance! : _init();
@@ -20,7 +22,7 @@ class PlatformUtil {
         print(e.stackTrace);
       }
     });
-    _instance = PlatformUtil();
+    _instance = PlatformUtil._();
     return _instance!;
   }
 
diff --git a/lib/src/web_storage/web_storage_manager.dart b/lib/src/web_storage/web_storage_manager.dart
index b6b2acfa..3174676a 100755
--- a/lib/src/web_storage/web_storage_manager.dart
+++ b/lib/src/web_storage/web_storage_manager.dart
@@ -22,6 +22,8 @@ class WebStorageManager {
   static WebStorageManager? _instance;
   static const MethodChannel _staticChannel = WEB_STORAGE_STATIC_CHANNEL;
 
+  WebStorageManager._();
+
   ///Use [WebStorageManager] instead.
   @Deprecated("Use WebStorageManager instead")
   AndroidWebStorageManager android = AndroidWebStorageManager();
@@ -44,7 +46,7 @@ class WebStorageManager {
         print(e.stackTrace);
       }
     });
-    _instance = new WebStorageManager();
+    _instance = new WebStorageManager._();
     return _instance!;
   }
 
diff --git a/macos/Classes/InAppBrowser/InAppBrowserSettings.swift b/macos/Classes/InAppBrowser/InAppBrowserSettings.swift
index 6b18dee8..91acead9 100755
--- a/macos/Classes/InAppBrowser/InAppBrowserSettings.swift
+++ b/macos/Classes/InAppBrowser/InAppBrowserSettings.swift
@@ -26,7 +26,7 @@ public class InAppBrowserSettings: ISettings<InAppBrowserWebViewController> {
         if let inAppBrowserWebViewController = obj {
             realOptions["hidden"] = inAppBrowserWebViewController.isHidden
             realOptions["hideUrlBar"] = inAppBrowserWebViewController.window?.searchBar?.isHidden
-            realOptions["progressBar"] = inAppBrowserWebViewController.progressBar.isHidden
+            realOptions["hideProgressBar"] = inAppBrowserWebViewController.progressBar.isHidden
             realOptions["hideToolbarTop"] = !(inAppBrowserWebViewController.window?.toolbar?.isVisible ?? true)
             realOptions["toolbarTopBackgroundColor"] = inAppBrowserWebViewController.window?.backgroundColor.hexString
         }