diff --git a/ChangeLog.md b/ChangeLog.md
new file mode 100644
--- /dev/null
+++ b/ChangeLog.md
@@ -0,0 +1,3 @@
+### 3.0.12
+
+Fix a mistake in the introspection data in [widgetGetParentwindow](https://hackage.haskell.org/package/gi-gtk/docs/GI-Gtk-Objects-Widget.html#v:widgetGetParentWindow), where the return value was not properly annotated as nullable. Fixes [#90](https://github.com/haskell-gi/haskell-gi/issues/90).
diff --git a/Gtk.overrides b/Gtk.overrides
--- a/Gtk.overrides
+++ b/Gtk.overrides
@@ -1,5 +1,7 @@
 namespace Gtk
 
+C-docs-url Gtk https://developer.gnome.org/gtk3/stable
+
 # We do not generate wrappers for GtkTreeModelModifyFunc, since it has
 # fairly weird semantics.
 ignore TreeModelFilter.set_modify_func
@@ -10,6 +12,20 @@
 # gtk_widget_path_iter_add_qclass isn't exported despite being present in Gtk-3.0.typelib
 # upstream issue: https://bugzilla.gnome.org/show_bug.cgi?id=761339
 ignore WidgetPath.iter_add_qclass
+
+# Wrong introspection annotation, see
+# https://bugzilla.gnome.org/show_bug.cgi?id=693393
+set-attr Gtk/PrintOperation/create-custom-widget/@return-value transfer-ownership full
+
+# This is nullable, but not marked as such, see
+# https://github.com/haskell-gi/haskell-gi/issues/90
+# https://bugzilla.gnome.org/show_bug.cgi?id=781246
+set-attr Gtk/Widget/get_parent_window/@return-value nullable 1
+
+# Wrong introspection data in old gtk versions, see
+# https://bugzilla.gnome.org/show_bug.cgi?id=674537
+set-attr Gtk/MenuPositionFunc/@parameters/x direction inout
+set-attr Gtk/MenuPositionFunc/@parameters/y direction inout
 
 if osx
     # Not supported in Quartz version of Gtk
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Documentation
 Autogenerated documentation for this package can be found at
 
-https://hackage.haskell.org/package/gi-gtk-3.0.11/docs/GI-Gtk.html
+[https://hackage.haskell.org/package/gi-gtk-3.0.12/docs/GI-Gtk.html](https://hackage.haskell.org/package/gi-gtk-3.0.12/docs/GI-Gtk.html)
 
 For general documentation on using [haskell-gi](https://github.com/haskell-gi/haskell-gi) based bindings, see [the project page](https://github.com/haskell-gi/haskell-gi) or [the Wiki](https://github.com/haskell-gi/haskell-gi/wiki).
diff --git a/gi-gtk.cabal b/gi-gtk.cabal
--- a/gi-gtk.cabal
+++ b/gi-gtk.cabal
@@ -1,5 +1,5 @@
 name:                 gi-gtk
-version:              3.0.11
+version:              3.0.12
 synopsis:             Gtk bindings
 description:          Bindings for Gtk, autogenerated by haskell-gi.
 homepage:             https://github.com/haskell-gi/haskell-gi
@@ -11,7 +11,7 @@
 build-type:           Custom
 cabal-version:        >= 1.24
 
-extra-source-files: README.md stack.yaml Gtk.overrides
+extra-source-files: README.md ChangeLog.md stack.yaml Gtk.overrides
 
 custom-setup
       setup-depends: base >= 4.7 && < 5,