diff --git a/generator/plugins/rust/rust_enum.py b/generator/plugins/rust/rust_enum.py
index c24a6de..e20265c 100644
--- a/generator/plugins/rust/rust_enum.py
+++ b/generator/plugins/rust/rust_enum.py
@@ -15,13 +15,19 @@ def _get_enum_docs(enum: Union[model.Enum, model.EnumItem]) -> List[str]:
 
 
 def generate_serde(enum: model.Enum) -> List[str]:
-    ser = [
+    ser = []
+    de = []
+    if enum.proposed:
+        ser += ["#[cfg(feature = \"proposed\")]"]
+        de  += ["#[cfg(feature = \"proposed\")]"]
+
+    ser += [
         f"impl Serialize for {enum.name} {{",
         "fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: serde::Serializer,{",
         "match self {",
     ]
 
-    de = [
+    de += [
         f"impl<'de> Deserialize<'de> for {enum.name} {{",
         f"fn deserialize<D>(deserializer: D) -> Result<{enum.name}, D::Error> where D: serde::Deserializer<'de>,"
         "{",
@@ -30,8 +36,12 @@ def generate_serde(enum: model.Enum) -> List[str]:
     ]
     for item in enum.values:
         full_name = f"{enum.name}::{to_upper_camel_case(item.name)}"
+        if item.proposed:
+            ser += ['#[cfg(feature = "proposed")]']
+            de += ['#[cfg(feature = "proposed")]']
         ser += [f"{full_name} => serializer.serialize_i32({item.value}),"]
         de += [f"{item.value} => Ok({full_name}),"]
+
     ser += [
         "}",  # match
         "}",  # fn
diff --git a/generator/plugins/rust/rust_structs.py b/generator/plugins/rust/rust_structs.py
index b6ca878..ec1f953 100644
--- a/generator/plugins/rust/rust_structs.py
+++ b/generator/plugins/rust/rust_structs.py
@@ -470,6 +470,7 @@ def generate_response(
         properties=properties,
         since=request_def.since,
         deprecated=request_def.deprecated,
+        proposed=request_def.proposed,
     )
 
     inner = []
diff --git a/packages/rust/lsprotocol/src/lib.rs b/packages/rust/lsprotocol/src/lib.rs
index e5a07b2..4323762 100644
--- a/packages/rust/lsprotocol/src/lib.rs
+++ b/packages/rust/lsprotocol/src/lib.rs
@@ -887,6 +887,7 @@ impl Serialize for MessageType {
             MessageType::Warning => serializer.serialize_i32(2),
             MessageType::Info => serializer.serialize_i32(3),
             MessageType::Log => serializer.serialize_i32(4),
+            #[cfg(feature = "proposed")]
             MessageType::Debug => serializer.serialize_i32(5),
         }
     }
@@ -902,6 +903,7 @@ impl<'de> Deserialize<'de> for MessageType {
             2 => Ok(MessageType::Warning),
             3 => Ok(MessageType::Info),
             4 => Ok(MessageType::Log),
+            #[cfg(feature = "proposed")]
             5 => Ok(MessageType::Debug),
             _ => Err(serde::de::Error::custom("Unexpected value")),
         }
@@ -1640,6 +1642,7 @@ pub enum InlineCompletionTriggerKind {
     /// Completion was triggered automatically while editing.
     Automatic = 2,
 }
+#[cfg(feature = "proposed")]
 impl Serialize for InlineCompletionTriggerKind {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -1651,6 +1654,7 @@ impl Serialize for InlineCompletionTriggerKind {
         }
     }
 }
+#[cfg(feature = "proposed")]
 impl<'de> Deserialize<'de> for InlineCompletionTriggerKind {
     fn deserialize<D>(deserializer: D) -> Result<InlineCompletionTriggerKind, D::Error>
     where
@@ -9996,6 +10000,7 @@ pub struct FoldingRangeRefreshRequest {
 }
 
 /// Response to the [FoldingRangeRefreshRequest].
+#[cfg(feature = "proposed")]
 #[derive(Serialize, Deserialize, PartialEq, Debug, Eq, Clone)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct FoldingRangeRefreshResponse {
@@ -10977,6 +10982,7 @@ pub struct InlineCompletionRequest {
 }
 
 /// Response to the [InlineCompletionRequest].
+#[cfg(feature = "proposed")]
 #[derive(Serialize, Deserialize, PartialEq, Debug, Eq, Clone)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct InlineCompletionResponse {
@@ -11015,6 +11021,7 @@ pub struct TextDocumentContentRequest {
 }
 
 /// Response to the [TextDocumentContentRequest].
+#[cfg(feature = "proposed")]
 #[derive(Serialize, Deserialize, PartialEq, Debug, Eq, Clone)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct TextDocumentContentResponse {
@@ -11052,6 +11059,7 @@ pub struct TextDocumentContentRefreshRequest {
 }
 
 /// Response to the [TextDocumentContentRefreshRequest].
+#[cfg(feature = "proposed")]
 #[derive(Serialize, Deserialize, PartialEq, Debug, Eq, Clone)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct TextDocumentContentRefreshResponse {
@@ -11957,6 +11965,7 @@ pub struct DocumentRangesFormattingRequest {
 }
 
 /// Response to the [DocumentRangesFormattingRequest].
+#[cfg(feature = "proposed")]
 #[derive(Serialize, Deserialize, PartialEq, Debug, Eq, Clone)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
 pub struct DocumentRangesFormattingResponse {