diff --git a/gst-libs/gst/interfaces/colorbalance.c b/gst-libs/gst/interfaces/colorbalance.c
index 319c1b9247..550598118c 100644
--- a/gst-libs/gst/interfaces/colorbalance.c
+++ b/gst-libs/gst/interfaces/colorbalance.c
@@ -41,6 +41,11 @@
  * </refsect2>
  */
 
+/* FIXME 0.11: check if we need to add API for sometimes-supportedness
+ * (aka making up for GstImplementsInterface removal) */
+
+/* FIXME 0.11: replace signals with messages (+ make API thread-safe) */
+
 enum
 {
   VALUE_CHANGED,
@@ -71,8 +76,6 @@ gst_color_balance_get_type (void)
 
     gst_color_balance_type = g_type_register_static (G_TYPE_INTERFACE,
         "GstColorBalance", &gst_color_balance_info, 0);
-    g_type_interface_add_prerequisite (gst_color_balance_type,
-        GST_TYPE_IMPLEMENTS_INTERFACE);
   }
 
   return gst_color_balance_type;
diff --git a/gst-libs/gst/interfaces/colorbalance.h b/gst-libs/gst/interfaces/colorbalance.h
index 62771b5027..896b6b62a3 100644
--- a/gst-libs/gst/interfaces/colorbalance.h
+++ b/gst-libs/gst/interfaces/colorbalance.h
@@ -28,16 +28,16 @@
 
 G_BEGIN_DECLS
 
+/* FIXME 0.11: remove all CLASS bits, this is an interface */
 #define GST_TYPE_COLOR_BALANCE \
   (gst_color_balance_get_type ())
 #define GST_COLOR_BALANCE(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_COLOR_BALANCE, \
-                                                 GstColorBalance))
+  (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_COLOR_BALANCE, GstColorBalance))
 #define GST_COLOR_BALANCE_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_COLOR_BALANCE, \
                             GstColorBalanceClass))
 #define GST_IS_COLOR_BALANCE(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_COLOR_BALANCE))
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_COLOR_BALANCE))
 #define GST_IS_COLOR_BALANCE_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_COLOR_BALANCE))
 #define GST_COLOR_BALANCE_GET_CLASS(inst) \
diff --git a/gst-libs/gst/interfaces/mixer.c b/gst-libs/gst/interfaces/mixer.c
index 8117d2081a..1e1b394f86 100644
--- a/gst-libs/gst/interfaces/mixer.c
+++ b/gst-libs/gst/interfaces/mixer.c
@@ -50,6 +50,9 @@
  * macro (in C) and the mixer API can be used.
  */
 
+/* FIXME 0.11: check if we need to add API for sometimes-supportedness
+ * (aka making up for GstImplementsInterface removal) */
+
 #ifndef GST_DISABLE_DEPRECATED
 enum
 {
@@ -86,8 +89,6 @@ gst_mixer_get_type (void)
 
     gst_mixer_type = g_type_register_static (G_TYPE_INTERFACE,
         "GstMixer", &gst_mixer_info, 0);
-    g_type_interface_add_prerequisite (gst_mixer_type,
-        GST_TYPE_IMPLEMENTS_INTERFACE);
   }
 
   return gst_mixer_type;
diff --git a/gst-libs/gst/interfaces/mixer.h b/gst-libs/gst/interfaces/mixer.h
index 71c8f7542f..ca7f3019c6 100644
--- a/gst-libs/gst/interfaces/mixer.h
+++ b/gst-libs/gst/interfaces/mixer.h
@@ -29,14 +29,16 @@
 
 G_BEGIN_DECLS
 
+/* FIXME 0.11: remove all CLASS bits, this is an interface */
+
 #define GST_TYPE_MIXER \
   (gst_mixer_get_type ())
 #define GST_MIXER(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_MIXER, GstMixer))
+  (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_MIXER, GstMixer))
 #define GST_MIXER_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_MIXER, GstMixerClass))
 #define GST_IS_MIXER(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_MIXER))
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_MIXER))
 #define GST_IS_MIXER_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_MIXER))
 #define GST_MIXER_GET_CLASS(inst) \
diff --git a/gst-libs/gst/interfaces/tuner.c b/gst-libs/gst/interfaces/tuner.c
index 2684517ab3..4e35dac1dc 100644
--- a/gst-libs/gst/interfaces/tuner.c
+++ b/gst-libs/gst/interfaces/tuner.c
@@ -69,6 +69,11 @@
  * </refsect2>
  */
 
+/* FIXME 0.11: check if we need to add API for sometimes-supportedness
+ * (aka making up for GstImplementsInterface removal) */
+
+/* FIXME 0.11: replace signals with messages (+ make API thread-safe) */
+
 enum
 {
   NORM_CHANGED,
@@ -102,8 +107,6 @@ gst_tuner_get_type (void)
 
     gst_tuner_type = g_type_register_static (G_TYPE_INTERFACE,
         "GstTuner", &gst_tuner_info, 0);
-    g_type_interface_add_prerequisite (gst_tuner_type,
-        GST_TYPE_IMPLEMENTS_INTERFACE);
   }
 
   return gst_tuner_type;
diff --git a/gst-libs/gst/interfaces/tuner.h b/gst-libs/gst/interfaces/tuner.h
index c728135b85..09158d4eab 100644
--- a/gst-libs/gst/interfaces/tuner.h
+++ b/gst-libs/gst/interfaces/tuner.h
@@ -29,14 +29,16 @@
 
 G_BEGIN_DECLS
 
+/* FIXME 0.11: remove all CLASS bits, this is an interface */
+
 #define GST_TYPE_TUNER \
   (gst_tuner_get_type ())
 #define GST_TUNER(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_TUNER, GstTuner))
+  (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_TUNER, GstTuner))
 #define GST_TUNER_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_TUNER, GstTunerClass))
 #define GST_IS_TUNER(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_TUNER))
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_TUNER))
 #define GST_IS_TUNER_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_TUNER))
 #define GST_TUNER_GET_CLASS(inst) \
diff --git a/gst-libs/gst/interfaces/videoorientation.c b/gst-libs/gst/interfaces/videoorientation.c
index 35ded695a0..4918862425 100644
--- a/gst-libs/gst/interfaces/videoorientation.c
+++ b/gst-libs/gst/interfaces/videoorientation.c
@@ -39,6 +39,9 @@
  * Since: 0.10.11
  */
 
+/* FIXME 0.11: check if we need to add API for sometimes-supportedness
+ * (aka making up for GstImplementsInterface removal) (probably yes) */
+
 static void gst_video_orientation_iface_init (GstVideoOrientationInterface *
     iface);
 
@@ -62,8 +65,6 @@ gst_video_orientation_get_type (void)
 
     gst_video_orientation_type = g_type_register_static (G_TYPE_INTERFACE,
         "GstVideoOrientation", &gst_video_orientation_info, 0);
-    g_type_interface_add_prerequisite (gst_video_orientation_type,
-        GST_TYPE_IMPLEMENTS_INTERFACE);
   }
 
   return gst_video_orientation_type;
diff --git a/gst-libs/gst/interfaces/videoorientation.h b/gst-libs/gst/interfaces/videoorientation.h
index c02d08b3f2..0ace82798e 100644
--- a/gst-libs/gst/interfaces/videoorientation.h
+++ b/gst-libs/gst/interfaces/videoorientation.h
@@ -30,9 +30,9 @@ G_BEGIN_DECLS
 #define GST_TYPE_VIDEO_ORIENTATION \
   (gst_video_orientation_get_type ())
 #define GST_VIDEO_ORIENTATION(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_VIDEO_ORIENTATION, GstVideoOrientation))
+  (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_VIDEO_ORIENTATION, GstVideoOrientation))
 #define GST_IS_VIDEO_ORIENTATION(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_VIDEO_ORIENTATION))
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_VIDEO_ORIENTATION))
 #define GST_VIDEO_ORIENTATION_GET_IFACE(inst) \
   (G_TYPE_INSTANCE_GET_INTERFACE ((inst), GST_TYPE_VIDEO_ORIENTATION, GstVideoOrientationInterface))
 
@@ -61,6 +61,10 @@ typedef struct _GstVideoOrientationInterface GstVideoOrientationInterface;
 struct _GstVideoOrientationInterface {
   GTypeInterface parent;
 
+  /* FIXME 0.11: fix awkward API? add some kind of get_supported flags thing
+   * and then just return booleans/int from all vfuncs requiring the caller
+   * to check the flags first */
+
   /* virtual functions */
   gboolean (* get_hflip)   (GstVideoOrientation *video_orientation, gboolean *flip);
   gboolean (* get_vflip)   (GstVideoOrientation *video_orientation, gboolean *flip);
diff --git a/gst-libs/gst/interfaces/xoverlay.c b/gst-libs/gst/interfaces/xoverlay.c
index 6fcb5ccad0..febf8c7a64 100644
--- a/gst-libs/gst/interfaces/xoverlay.c
+++ b/gst-libs/gst/interfaces/xoverlay.c
@@ -318,8 +318,6 @@ gst_x_overlay_get_type (void)
 
     gst_x_overlay_type = g_type_register_static (G_TYPE_INTERFACE,
         "GstXOverlay", &gst_x_overlay_info, 0);
-    g_type_interface_add_prerequisite (gst_x_overlay_type,
-        GST_TYPE_IMPLEMENTS_INTERFACE);
   }
 
   return gst_x_overlay_type;
diff --git a/gst-libs/gst/interfaces/xoverlay.h b/gst-libs/gst/interfaces/xoverlay.h
index 6ac355c25f..d0ece43f26 100644
--- a/gst-libs/gst/interfaces/xoverlay.h
+++ b/gst-libs/gst/interfaces/xoverlay.h
@@ -27,15 +27,16 @@
 
 G_BEGIN_DECLS
 
+/* FIXME 0.11: remove all CLASS bits, this is an interface */
+
 #define GST_TYPE_X_OVERLAY \
   (gst_x_overlay_get_type ())
 #define GST_X_OVERLAY(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_X_OVERLAY, \
-                                                 GstXOverlay))
+  (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_X_OVERLAY, GstXOverlay))
 #define GST_X_OVERLAY_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_X_OVERLAY, GstXOverlayClass))
 #define GST_IS_X_OVERLAY(obj) \
-  (GST_IMPLEMENTS_INTERFACE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_X_OVERLAY))
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_X_OVERLAY))
 #define GST_IS_X_OVERLAY_CLASS(klass) \
   (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_X_OVERLAY))
 #define GST_X_OVERLAY_GET_CLASS(inst) \