diff --git a/evolution-2.27.4-gmount-deprecation.patch b/evolution-2.27.4-gmount-deprecation.patch
new file mode 100644
index 0000000..b917127
--- /dev/null
+++ b/evolution-2.27.4-gmount-deprecation.patch
@@ -0,0 +1,27 @@
+diff -up evolution-2.27.4/plugins/publish-calendar/publish-calendar.c.gmount-deprecation evolution-2.27.4/plugins/publish-calendar/publish-calendar.c
+--- evolution-2.27.4/plugins/publish-calendar/publish-calendar.c.gmount-deprecation	2009-07-13 03:45:13.000000000 -0400
++++ evolution-2.27.4/plugins/publish-calendar/publish-calendar.c	2009-07-13 14:32:58.000000000 -0400
+@@ -129,7 +129,11 @@ unmount_done_cb (GObject *source_object,
+ {
+ 	GError *error = NULL;
+ 
++#if GLIB_CHECK_VERSION(2,21,4)
++	g_mount_unmount_with_operation_finish (G_MOUNT (source_object), res, &error);
++#else
+ 	g_mount_unmount_finish (G_MOUNT (source_object), res, &error);
++#endif
+ 
+ 	if (error) {
+ 		g_warning ("Unmount failed: %s", error->message);
+@@ -177,7 +181,11 @@ mount_ready_cb (GObject *source_object, 
+ 
+ 	mount = g_file_find_enclosing_mount (G_FILE (source_object), NULL, NULL);
+ 	if (mount)
++#if GLIB_CHECK_VERSION(2,21,4)
++		g_mount_unmount_with_operation (mount, G_MOUNT_UNMOUNT_NONE, NULL, NULL, unmount_done_cb, NULL);
++#else
+ 		g_mount_unmount (mount, G_MOUNT_UNMOUNT_NONE, NULL, unmount_done_cb, NULL);
++#endif
+ 
+ 	g_object_unref (source_object);
+ }
diff --git a/evolution.spec b/evolution.spec
index bc0e921..1f34a42 100644
--- a/evolution.spec
+++ b/evolution.spec
@@ -69,6 +69,9 @@ Patch12: evolution-2.9.1-im-context-reset.patch
 # Let the pst-import plugin work with current libpst.
 Patch14: evolution-2.27.3-pst-import.patch
 
+# Work around deprecation of g_mount_unmount().
+Patch15: evolution-2.27.4-gmount-deprecation.patch
+
 ## Dependencies ###
 
 Requires(post): GConf2
@@ -243,6 +246,7 @@ This package contains the plugin to import Microsoft Personal Storage Table
 %patch11 -p1 -b .fix-conduit-dir
 %patch12 -p1 -b .im-context-reset
 %patch14 -p1 -b .pst-import
+%patch15 -p1 -b .gmount-deprecation
 
 mkdir -p krb5-fakeprefix/include
 mkdir -p krb5-fakeprefix/lib
@@ -699,6 +703,7 @@ rm -rf $RPM_BUILD_ROOT
 %changelog
 * Mon Jul 13 2009 Matthew Barnes <mbarnes@redhat.com> - 2.27.4-1.fc12
 - Update to 2.27.4
+- Work around deprecation of g_mount_unmount().
 
 * Fri Jul 10 2009 Matthew Barnes <mbarnes@redhat.com> - 2.27.3-5.fc11
 - Add an evolution-pst subpackage for the PST importer plugin.