diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,6 +1,10 @@
+### 3.0.21
+
++ The return value of [`widgetDragDestFindTarget`](https://hackage.haskell.org/package/gi-gtk/docs/GI-Gtk-Objects-Widget.html#v:widgetDragDestFindTarget) is nullable, but was not marked as such.
+
 ### 3.0.20
 
-+ Make the 'events' parameter to ['widgetAddEvents'](https://hackage.haskell.org/package/gi-gtk/docs/GI-Gtk-Objects-Widget.html#v:widgetAddEvents) and ['widgetSetEvents](https://hackage.haskell.org/package/gi-gtk/docs/GI-Gtk-Objects-Widget.html#v:widgetSetEvents) a [GdkEventMask](https://hackage.haskell.org/package/gi-gdk/docs/GI-Gdk-Flags.html#t:EventMask), see [issue 136](https://github.com/haskell-gi/haskell-gi/issues/136).
++ Make the `events` parameter to [`widgetAddEvents`](https://hackage.haskell.org/package/gi-gtk/docs/GI-Gtk-Objects-Widget.html#v:widgetAddEvents) and [`widgetSetEvents`](https://hackage.haskell.org/package/gi-gtk/docs/GI-Gtk-Objects-Widget.html#v:widgetSetEvents) a [`GdkEventMask`](https://hackage.haskell.org/package/gi-gdk/docs/GI-Gdk-Flags.html#t:EventMask), see [issue 136](https://github.com/haskell-gi/haskell-gi/issues/136).
 
 ### 3.0.19
 
diff --git a/Gtk.overrides b/Gtk.overrides
--- a/Gtk.overrides
+++ b/Gtk.overrides
@@ -54,6 +54,10 @@
 set-attr Gtk/Widget/set_events/@parameters/events/@type name Gdk.EventMask
 set-attr Gtk/Widget/set_events/@parameters/events/@type c:type GdkEventMask
 
+# https://github.com/haskell-gi/haskell-gi/issues/138
+# https://gitlab.gnome.org/GNOME/gtk/issues/84
+set-attr Gtk/Widget/drag_dest_find_target/@return-value nullable 1
+
 if osx
     # Not supported in Quartz version of Gtk
     ignore drag_set_icon_gicon
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-3.0.19/docs/GI-Gtk.html](https://hackage.haskell.org/package/gi-gtk-3.0.19/docs/GI-Gtk.html)
+[https://hackage.haskell.org/package/gi-gtk-3.0.21/docs/GI-Gtk.html](https://hackage.haskell.org/package/gi-gtk-3.0.21/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:              3.0.20
+version:              3.0.21
 synopsis:             Gtk bindings
 description:          Bindings for Gtk, autogenerated by haskell-gi.
 homepage:             https://github.com/haskell-gi/haskell-gi