diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+### 2.0.16
+
++ The return value of [`volumeGetMount`](https://hackage.haskell.org/package/gi-gio/docs/GI-Gio-Interfaces-Volume.html#v:volumeGetMount) is nullable, but was not marked as such.
+
 ### 2.0.15
 
 + Remove enable-overloading flags, and use instead explicit CPP checks for 'haskell-gi-overloading-1.0', see [how to disable overloading](https://github.com/haskell-gi/haskell-gi/wiki/Overloading\#disabling-overloading).
diff --git a/Gio.overrides b/Gio.overrides
--- a/Gio.overrides
+++ b/Gio.overrides
@@ -13,6 +13,10 @@
 # Properly marked as filename in recent Gio versions.
 set-attr Gio/AppInfo/get_executable/@return-value/@type name filename
 
+# Return value is nullable, but not marked as such.
+# https://github.com/haskell-gi/haskell-gi/issues/139
+set-attr Gio/Volume/get_mount/@return-value nullable 1
+
 # Not supported on Windows.
 if windows
    ignore DBusMessage.get_unix_fd_list
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-gio-2.0.15/docs/GI-Gio.html](https://hackage.haskell.org/package/gi-gio-2.0.15/docs/GI-Gio.html)
+[https://hackage.haskell.org/package/gi-gio-2.0.16/docs/GI-Gio.html](https://hackage.haskell.org/package/gi-gio-2.0.16/docs/GI-Gio.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-gio.cabal b/gi-gio.cabal
--- a/gi-gio.cabal
+++ b/gi-gio.cabal
@@ -1,5 +1,5 @@
 name:                 gi-gio
-version:              2.0.15
+version:              2.0.16
 synopsis:             Gio bindings
 description:          Bindings for Gio, autogenerated by haskell-gi.
 homepage:             https://github.com/haskell-gi/haskell-gi