diff --git a/src/client/conn/http1.rs b/src/client/conn/http1.rs
index c487b1927a..8eaaa5ee64 100644
--- a/src/client/conn/http1.rs
+++ b/src/client/conn/http1.rs
@@ -97,6 +97,9 @@ where
 /// A builder to configure an HTTP connection.
 ///
 /// After setting options, the builder is used to create a handshake future.
+/// 
+/// **Note**: The default values of options are *not considered stable*. They 
+/// are subject to change at any time
 #[derive(Clone, Debug)]
 pub struct Builder {
     h09_responses: bool,
diff --git a/src/client/conn/http2.rs b/src/client/conn/http2.rs
index ec8ecf3e08..5b7d02b751 100644
--- a/src/client/conn/http2.rs
+++ b/src/client/conn/http2.rs
@@ -50,6 +50,9 @@ where
 /// A builder to configure an HTTP connection.
 ///
 /// After setting options, the builder is used to create a handshake future.
+/// 
+/// **Note**: The default values of options are *not considered stable*. They 
+/// are subject to change at any time
 #[derive(Clone, Debug)]
 pub struct Builder<Ex> {
     pub(super) exec: Ex,
diff --git a/src/server/conn/http1.rs b/src/server/conn/http1.rs
index d4b8924e9f..ccce8d7a50 100644
--- a/src/server/conn/http1.rs
+++ b/src/server/conn/http1.rs
@@ -41,6 +41,9 @@ pin_project_lite::pin_project! {
 }
 
 /// A configuration builder for HTTP/1 server connections.
+/// 
+/// **Note**: The default values of options are *not considered stable*. They 
+/// are subject to change at any time
 #[derive(Clone, Debug)]
 pub struct Builder {
     timer: Time,
diff --git a/src/server/conn/http2.rs b/src/server/conn/http2.rs
index 1af3d4a36e..4ef4b7f0f2 100644
--- a/src/server/conn/http2.rs
+++ b/src/server/conn/http2.rs
@@ -35,6 +35,9 @@ pin_project! {
 }
 
 /// A configuration builder for HTTP/2 server connections.
+/// 
+/// **Note**: The default values of options are *not considered stable*. They 
+/// are subject to change at any time
 #[derive(Clone, Debug)]
 pub struct Builder<E> {
     exec: E,