diff --git a/ruma-client-api/src/r0/keys/get_keys.rs b/ruma-client-api/src/r0/keys/get_keys.rs
index 8f98c17b..60629ad7 100644
--- a/ruma-client-api/src/r0/keys/get_keys.rs
+++ b/ruma-client-api/src/r0/keys/get_keys.rs
@@ -45,10 +45,27 @@ ruma_api! {
         /// If any remote homeservers could not be reached, they are recorded
         /// here. The names of the properties are the names of the unreachable
         /// servers.
+        #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
         pub failures: BTreeMap<String, JsonValue>,
 
         /// Information on the queried devices.
+        #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
         pub device_keys: BTreeMap<UserId, BTreeMap<Box<DeviceId>, DeviceKeys>>,
+
+        /// Information on the master cross-signing keys of the queried users.
+        #[cfg(feature = "unstable-pre-spec")]
+        #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+        pub master_keys: BTreeMap<UserId, super::CrossSigningKey>,
+
+        /// Information on the self-signing keys of the queried users.
+        #[cfg(feature = "unstable-pre-spec")]
+        #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+        pub self_signing_keys: BTreeMap<UserId, super::CrossSigningKey>,
+
+        /// Information on the user-signing keys of the queried users.
+        #[cfg(feature = "unstable-pre-spec")]
+        #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+        pub user_signing_keys: BTreeMap<UserId, super::CrossSigningKey>,
     }
 
     error: crate::Error