diff --git a/osu.Game/Online/Notifications/WebSocket/Events/UserAchievementUnlock.cs b/osu.Game/Online/Notifications/WebSocket/Events/UserAchievementUnlock.cs
index 6c7c8af4f4..3f803a4fe5 100644
--- a/osu.Game/Online/Notifications/WebSocket/Events/UserAchievementUnlock.cs
+++ b/osu.Game/Online/Notifications/WebSocket/Events/UserAchievementUnlock.cs
@@ -14,7 +14,7 @@ namespace osu.Game.Online.Notifications.WebSocket.Events
         public uint AchievementId { get; set; }
 
         [JsonProperty("achievement_mode")]
-        public ushort? AchievementMode { get; set; }
+        public string? AchievementMode { get; set; }
 
         [JsonProperty("cover_url")]
         public string CoverUrl { get; set; } = string.Empty;