diff --git a/crates/ruma-client-api/src/r0/uiaa.rs b/crates/ruma-client-api/src/r0/uiaa.rs
index 006ca1fb..950247d9 100644
--- a/crates/ruma-client-api/src/r0/uiaa.rs
+++ b/crates/ruma-client-api/src/r0/uiaa.rs
@@ -861,6 +861,7 @@ impl OutgoingResponse for UiaaResponse {
     }
 }
 
+#[cfg(feature = "compat")]
 fn deserialize_thirdparty_id_creds<'de, D>(
     deserializer: D,
 ) -> Result<Vec<ThirdpartyIdCredentials>, D::Error>