diff --git a/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs b/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs
index f14215e8..87ecea90 100644
--- a/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs
+++ b/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs
@@ -122,6 +122,20 @@ public class ActivityHandlerService(
 				await noteSvc.LikeNoteAsync(note, activity.Actor);
 				return;
 			}
+			case ASUpdate: {
+				switch (activity.Object) {
+					case ASActor actor:
+						if (actor.Id != activity.Actor.Id)
+							throw GracefulException.UnprocessableEntity("Refusing to update actor with mismatching id");
+						await userSvc.UpdateUserAsync(resolvedActor, actor);
+						return;
+					case ASNote note:
+						throw new NotImplementedException("Note updates haven't been implemented yet");
+						//return;
+					default:
+						throw GracefulException.UnprocessableEntity("Update activity object is invalid");
+				}
+			}
 			default: {
 				throw new NotImplementedException($"Activity type {activity.Type} is unknown");
 			}
diff --git a/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASActivity.cs b/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASActivity.cs
index bf91731e..74aba627 100644
--- a/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASActivity.cs
+++ b/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASActivity.cs
@@ -17,6 +17,7 @@ public class ASActivity : ASObject {
 		private const string Ns = Constants.ActivityStreamsNs;
 
 		public const string Create   = $"{Ns}#Create";
+		public const string Update   = $"{Ns}#Update";
 		public const string Delete   = $"{Ns}#Delete";
 		public const string Follow   = $"{Ns}#Follow";
 		public const string Unfollow = $"{Ns}#Unfollow";
@@ -59,6 +60,10 @@ public class ASLike : ASActivity {
 	public ASLike() => Type = Types.Like;
 }
 
+public class ASUpdate : ASActivity {
+	public ASUpdate() => Type = Types.Update;
+}
+
 //TODO: add the rest
 
 public sealed class ASActivityConverter : ASSerializer.ListSingleObjectConverter<ASActivity>;
\ No newline at end of file
diff --git a/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASObject.cs b/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASObject.cs
index 63a72d73..1612a6ce 100644
--- a/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASObject.cs
+++ b/Iceshrimp.Backend/Core/Federation/ActivityStreams/Types/ASObject.cs
@@ -37,6 +37,7 @@ public class ASObject : ASObjectBase {
 						ASNote.Types.Note          => token.ToObject<ASNote>(),
 						Types.Tombstone            => token.ToObject<ASTombstone>(),
 						ASActivity.Types.Create    => token.ToObject<ASCreate>(),
+						ASActivity.Types.Update    => token.ToObject<ASUpdate>(),
 						ASActivity.Types.Delete    => token.ToObject<ASDelete>(),
 						ASActivity.Types.Follow    => token.ToObject<ASFollow>(),
 						ASActivity.Types.Unfollow  => token.ToObject<ASUnfollow>(),
diff --git a/Iceshrimp.Backend/Core/Services/UserService.cs b/Iceshrimp.Backend/Core/Services/UserService.cs
index e5cf21b7..ff45850d 100644
--- a/Iceshrimp.Backend/Core/Services/UserService.cs
+++ b/Iceshrimp.Backend/Core/Services/UserService.cs
@@ -145,8 +145,10 @@ public class UserService(
 		}
 	}
 
-	public async Task<User> UpdateUserAsync(User user) {
-		if (!user.NeedsUpdate) return user;
+	public async Task<User> UpdateUserAsync(User user, ASActor? actor = null) {
+		if (!user.NeedsUpdate && actor == null) return user;
+		if (actor is { IsUnresolved: true } or { Username: null })
+			actor = null; // This will trigger a fetch a couple lines down
 
 		// Prevent multiple update jobs from running concurrently
 		db.Update(user);
@@ -156,7 +158,7 @@ public class UserService(
 		var uri = user.Uri ?? throw new Exception("Encountered remote user without a Uri");
 		logger.LogDebug("Updating user with uri {uri}", uri);
 
-		var actor = await fetchSvc.FetchActorAsync(user.Uri);
+		actor ??= await fetchSvc.FetchActorAsync(user.Uri);
 		actor.Normalize(uri, user.AcctWithPrefix);
 
 		user.UserProfile ??= await db.UserProfiles.FirstOrDefaultAsync(p => p.User == user);