diff --git a/rust/src/config/mod.rs b/rust/src/config/mod.rs
index 6dd4ae220a..562beebfc9 100644
--- a/rust/src/config/mod.rs
+++ b/rust/src/config/mod.rs
@@ -21,6 +21,8 @@ use pyo3::{exceptions::PyRuntimeError, prelude::*};
 #[derive(FromPyObject, Clone)]
 pub struct SynapseConfig {
     pub room: RoomConfig,
+    pub auth: AuthConfig,
+    pub server: ServerConfig,
     pub experimental: ExperimentalConfig,
 }
 
@@ -62,6 +64,15 @@ pub struct RoomConfig {
     pub encryption_enabled_by_default_for_room_presets: BTreeSet<RoomCreationPreset>,
 }
 
+#[derive(FromPyObject, Clone)]
+pub struct AuthConfig {
+    pub login_via_existing_enabled: bool,
+}
+#[derive(FromPyObject, Clone)]
+pub struct ServerConfig {
+    pub max_event_delay_ms: Option<u64>,
+}
+
 #[derive(FromPyObject, Clone)]
 pub struct ExperimentalConfig {
     pub msc3026_enabled: bool,
diff --git a/rust/src/handlers/versions.rs b/rust/src/handlers/versions.rs
index d2627b9e79..fde47f4a33 100644
--- a/rust/src/handlers/versions.rs
+++ b/rust/src/handlers/versions.rs
@@ -304,7 +304,10 @@ pub fn synapse_config_to_global_unstable_feature_map(config: &SynapseConfig) ->
         msc4028: config.experimental.msc4028_push_encrypted_events,
         msc4108: config.experimental.msc4108_enabled
             || (config.experimental.msc4108_delegation_endpoint.is_some()),
-        msc4140: bool(config.server.max_event_delay_ms),
+        msc4140: config
+            .server
+            .max_event_delay_ms
+            .is_some_and(|max_event_delay_ms| max_event_delay_ms > 0),
         msc3575: config.experimental.msc3575_enabled,
         msc4133: config.experimental.msc4133_enabled,
         msc4133_stable: true,