diff --git a/src/codec/framed_read.rs b/src/codec/framed_read.rs
index 16efd70..c4792f9 100644
--- a/src/codec/framed_read.rs
+++ b/src/codec/framed_read.rs
@@ -221,12 +221,14 @@ impl<T> FramedRead<T> {
     }
 
     /// Returns the current max frame size setting
+    #[cfg(feature = "unstable")]
     #[inline]
     pub fn max_frame_size(&self) -> usize {
         self.inner.max_frame_length()
     }
 
     /// Updates the max frame size setting.
+    #[cfg(feature = "unstable")]
     #[inline]
     pub fn set_max_frame_size(&mut self, val: usize) {
         self.inner.set_max_frame_length(val)
diff --git a/src/codec/mod.rs b/src/codec/mod.rs
index 01db79b..a4cf71a 100644
--- a/src/codec/mod.rs
+++ b/src/codec/mod.rs
@@ -63,6 +63,7 @@ impl<T, B> Codec<T, B> {
     /// words, if a frame is currently in process of being decoded with a frame
     /// size greater than `val` but less than the max frame size in effect
     /// before calling this function, then the frame will be allowed.
+    #[cfg(feature = "unstable")]
     #[inline]
     pub fn set_max_recv_frame_size(&mut self, val: usize) {
         // TODO: should probably make some assertions about max frame size...
@@ -73,6 +74,7 @@ impl<T, B> Codec<T, B> {
     ///
     /// This is the largest size this codec will accept from the wire. Larger
     /// frames will be rejected.
+    #[cfg(feature = "unstable")]
     #[inline]
     pub fn max_recv_frame_size(&self) -> usize {
         self.inner.max_frame_size()
diff --git a/src/frame/go_away.rs b/src/frame/go_away.rs
index 4b7c4d2..7dacaf5 100644
--- a/src/frame/go_away.rs
+++ b/src/frame/go_away.rs
@@ -16,6 +16,7 @@ impl GoAway {
         }
     }
 
+    #[cfg(feature = "unstable")]
     pub fn last_stream_id(&self) -> StreamId {
         self.last_stream_id
     }