diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6ae2dc3d..4c7b61d3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ Breaking changes:
 
 * The `event_id` in the response for the message and state sending endpoints is now required
   * r0.6.0 doesn't say they are required, but this has been fixed for the next version of the spec
+* Updated the type of `r0::sync::sync_events::DeviceLists` fields
 
 Improvements:
 
diff --git a/src/r0/sync/sync_events.rs b/src/r0/sync/sync_events.rs
index bb02b62e..2a6c4828 100644
--- a/src/r0/sync/sync_events.rs
+++ b/src/r0/sync/sync_events.rs
@@ -330,12 +330,12 @@ pub struct DeviceLists {
     /// List of users who have updated their device identity keys or who now
     /// share an encrypted room with the client since the previous sync
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
-    pub changed: Vec<String>,
+    pub changed: Vec<UserId>,
 
     /// List of users who no longer share encrypted rooms since the previous sync
     /// response.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
-    pub left: Vec<String>,
+    pub left: Vec<UserId>,
 }
 
 #[cfg(test)]