diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6ef2fa0..a4f3405 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## [0.1.4] - 10 Nov 2020
+
+ - Update nullOk Parameter for flutter 1.23
+
 ## [0.1.3] - 15 Juli 2019
 
  - Remove obsolete import
diff --git a/example/pubspec.lock b/example/pubspec.lock
index 3ecb8d0..efceb5e 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -7,28 +7,42 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.0"
+    version: "2.5.0-nullsafety.2"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "2.1.0-nullsafety.2"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0-nullsafety.4"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.2"
+    version: "1.2.0-nullsafety.2"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0-nullsafety.2"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.11"
+    version: "1.15.0-nullsafety.4"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -36,6 +50,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.1.2"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0-nullsafety.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -59,35 +80,21 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.5"
+    version: "0.12.10-nullsafety.2"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.5"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.2"
-  pedantic:
-    dependency: transitive
-    description:
-      name: pedantic
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.7.0"
-  quiver:
-    dependency: transitive
-    description:
-      name: quiver
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.0.3"
+    version: "1.8.0-nullsafety.2"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -99,55 +106,55 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.5.5"
+    version: "1.8.0-nullsafety.3"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.3"
+    version: "1.10.0-nullsafety.5"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0-nullsafety.2"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "1.1.0-nullsafety.2"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0-nullsafety.2"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.5"
+    version: "0.2.19-nullsafety.4"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.4"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0-nullsafety.4"
 sdks:
-  dart: ">=2.2.2 <3.0.0"
+  dart: ">=2.11.0-0.0 <2.12.0"
diff --git a/lib/gradient_app_bar.dart b/lib/gradient_app_bar.dart
index bab5f08..c635b9b 100644
--- a/lib/gradient_app_bar.dart
+++ b/lib/gradient_app_bar.dart
@@ -404,7 +404,7 @@ class _GradientAppBarState extends State<GradientAppBar> {
     assert(debugCheckHasMaterialLocalizations(context));
     final ThemeData themeData = Theme.of(context);
     final AppBarTheme appBarTheme = AppBarTheme.of(context);
-    final ScaffoldState scaffold = Scaffold.of(context, nullOk: true);
+    final ScaffoldState scaffold = Scaffold.maybeOf(context);
     final ModalRoute<dynamic> parentRoute = ModalRoute.of(context);
 
     final bool hasDrawer = scaffold?.hasDrawer ?? false;
@@ -427,8 +427,8 @@ class _GradientAppBarState extends State<GradientAppBar> {
 
     if (widget.toolbarOpacity != 1.0) {
       final double opacity =
-      const Interval(0.25, 1.0, curve: Curves.fastOutSlowIn)
-          .transform(widget.toolbarOpacity);
+          const Interval(0.25, 1.0, curve: Curves.fastOutSlowIn)
+              .transform(widget.toolbarOpacity);
       if (centerStyle?.color != null)
         centerStyle =
             centerStyle.copyWith(color: centerStyle.color.withOpacity(opacity));
@@ -542,11 +542,11 @@ class _GradientAppBarState extends State<GradientAppBar> {
           widget.bottomOpacity == 1.0
               ? widget.bottom
               : Opacity(
-            opacity:
-            const Interval(0.25, 1.0, curve: Curves.fastOutSlowIn)
-                .transform(widget.bottomOpacity),
-            child: widget.bottom,
-          ),
+                  opacity:
+                      const Interval(0.25, 1.0, curve: Curves.fastOutSlowIn)
+                          .transform(widget.bottomOpacity),
+                  child: widget.bottom,
+                ),
         ],
       );
     }
@@ -587,7 +587,7 @@ class _GradientAppBarState extends State<GradientAppBar> {
         child: Material(
             color: appBarTheme.color ?? themeData.primaryColor,
             elevation:
-            widget.elevation ?? appBarTheme.elevation ?? _defaultElevation,
+                widget.elevation ?? appBarTheme.elevation ?? _defaultElevation,
             shape: widget.shape,
             child: Container(
               decoration: BoxDecoration(gradient: widget.gradient),
@@ -633,8 +633,8 @@ class _FloatingGradientAppBarState extends State<_FloatingGradientAppBar> {
   }
 
   RenderSliverFloatingPersistentHeader _headerRenderer() {
-    return context.ancestorRenderObjectOfType(
-        const TypeMatcher<RenderSliverFloatingPersistentHeader>());
+    return context
+        .findAncestorRenderObjectOfType<RenderSliverFloatingPersistentHeader>();
   }
 
   void _isScrollingListener() {
diff --git a/pubspec.lock b/pubspec.lock
index 7642229..2a6d844 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -7,28 +7,49 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.0"
+    version: "2.5.0-nullsafety.2"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "2.1.0-nullsafety.2"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0-nullsafety.4"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.2"
+    version: "1.2.0-nullsafety.2"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0-nullsafety.2"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.11"
+    version: "1.15.0-nullsafety.4"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0-nullsafety.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -45,35 +66,21 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.5"
+    version: "0.12.10-nullsafety.2"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.5"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.2"
-  pedantic:
-    dependency: transitive
-    description:
-      name: pedantic
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.7.0"
-  quiver:
-    dependency: transitive
-    description:
-      name: quiver
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.0.3"
+    version: "1.8.0-nullsafety.2"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -85,55 +92,56 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.5.5"
+    version: "1.8.0-nullsafety.3"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.3"
+    version: "1.10.0-nullsafety.5"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0-nullsafety.2"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "1.1.0-nullsafety.2"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0-nullsafety.2"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.5"
+    version: "0.2.19-nullsafety.4"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.4"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0-nullsafety.4"
 sdks:
-  dart: ">=2.2.2 <3.0.0"
+  dart: ">=2.11.0-0.0 <2.12.0"
+  flutter: ">=1.23.0 <2.0.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index c72c405..2be7b0e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: gradient_app_bar
 description: The official AppBar, with a more colorful twist. Add gradients to spice up your application and make it beautiful. This easy to use library makes it easy, and most of all, it is compatible with everything the normal AppBar is compatible with!
-version: 0.1.3
+version: 0.1.4
 author: Joost Lekkerkerker <joostlek@outlook.com>
 homepage: https://github.com/joostlek/GradientAppBar
 
@@ -13,7 +13,8 @@ dev_dependencies:
     sdk: flutter
 
 environment:
-  sdk: '>=1.19.0 <3.0.0'
+  flutter: ">=1.23.0 <2.0.0"
+  sdk: ">=2.10.0 <3.0.0"
 
 # For information on the generic Dart part of this file, see the
 # following page: https://www.dartlang.org/tools/pub/pubspec