diff --git a/src/api/client/room/create.rs b/src/api/client/room/create.rs
index adf69568..efde40dd 100644
--- a/src/api/client/room/create.rs
+++ b/src/api/client/room/create.rs
@@ -194,6 +194,7 @@ pub(crate) async fn create_room_route(
 
 	// 1. The room create event
 	debug!("Creating room create event for {sender_user} in room {room_id:?}");
+	let tmp_id = room_id.as_deref();
 	let create_event_id = services
 		.rooms
 		.timeline
@@ -205,13 +206,13 @@ pub(crate) async fn create_room_route(
 				..Default::default()
 			},
 			sender_user,
-			None,
+			tmp_id,
 			&state_lock,
 		)
 		.boxed()
 		.await?;
-	trace!("Created room create event with ID {}", create_event_id);
-	let room_id = match room_id {
+	trace!("Created room create event with ID {}", &create_event_id);
+	let room_id = match room_id.clone() {
 		| Some(room_id) => room_id,
 		| None => {
 			let as_room_id = create_event_id.as_str().replace('$', "!");
@@ -287,6 +288,10 @@ pub(crate) async fn create_room_route(
 				}
 			}
 		}
+	} else {
+		users.insert(sender_user.to_owned(), int!(100));
+		creators.clear(); // If this vec is not empty, default_power_levels_content will
+		// treat this as a v12 room
 	}
 
 	let power_levels_content = default_power_levels_content(
diff --git a/src/core/matrix/state_res/event_auth.rs b/src/core/matrix/state_res/event_auth.rs
index 12929278..9f5c4fed 100644
--- a/src/core/matrix/state_res/event_auth.rs
+++ b/src/core/matrix/state_res/event_auth.rs
@@ -587,6 +587,26 @@ where
 	Ok(true)
 }
 
+fn is_creator<EV>(v: &RoomVersion, c: &BTreeSet<OwnedUserId>, ce: &EV, user_id: &UserId) -> bool
+where
+	EV: Event + Send + Sync,
+{
+	if v.explicitly_privilege_room_creators {
+		c.contains(user_id)
+	} else if v.use_room_create_sender {
+		ce.sender() == user_id
+	} else {
+		#[allow(deprecated)]
+		let creator = from_json_str::<RoomCreateEventContent>(ce.content().get())
+			.unwrap()
+			.creator
+			.ok_or_else(|| serde_json::Error::missing_field("creator"))
+			.unwrap();
+
+		creator == user_id
+	}
+}
+
 // TODO deserializing the member, power, join_rules event contents is done in
 // conduit just before this is called. Could they be passed in?
 /// Does the user who sent this member event have required power levels to do
@@ -618,9 +638,6 @@ where
 	E: Event + Send + Sync,
 	for<'a> &'a E: Event + Send,
 {
-	fn is_creator(v: &RoomVersion, c: &BTreeSet<OwnedUserId>, user_id: &UserId) -> bool {
-		c.contains(user_id) && v.explicitly_privilege_room_creators
-	}
 	#[derive(Deserialize)]
 	struct GetThirdPartyInvite {
 		third_party_invite: Option<Raw<ThirdPartyInvite>>,
@@ -677,6 +694,7 @@ where
 			target_power = Some(&Int::MAX);
 		}
 	}
+	trace!(?creators, "creators for room");
 
 	let mut join_rules = JoinRule::Invite;
 	if let Some(jr) = &join_rules_event {
@@ -707,7 +725,7 @@ where
 			(int!(0), int!(0))
 		};
 		let user_joined = user_for_join_auth_membership == &MembershipState::Join;
-		let okay_power = is_creator(room_version, &creators, user_for_join_auth)
+		let okay_power = is_creator(room_version, &creators, create_room, user_for_join_auth)
 			|| auth_user_pl >= invite_level;
 		user_joined && okay_power
 	} else {
@@ -715,8 +733,8 @@ where
 		false
 	};
 
-	let sender_creator = is_creator(room_version, &creators, sender);
-	let target_creator = is_creator(room_version, &creators, target_user);
+	let sender_creator = is_creator(room_version, &creators, create_room, sender);
+	let target_creator = is_creator(room_version, &creators, create_room, target_user);
 
 	Ok(match target_membership {
 		| MembershipState::Join => {
@@ -732,15 +750,14 @@ where
 			let no_more_prev_events = prev_events.next().is_none();
 
 			if prev_event_is_create_event && no_more_prev_events {
-				trace!("checking if sender is a room creator for initial membership event");
-				let is_creator = (sender_creator && target_creator) || {
-					#[allow(deprecated)]
-					let creator = from_json_str::<RoomCreateEventContent>(create_room.content().get())?
-						.creator
-						.ok_or_else(|| serde_json::Error::missing_field("creator"))?;
-
-					creator == sender && creator == target_user
-				};
+				trace!(
+					sender = %sender,
+					target_user = %target_user,
+					?sender_creator,
+					?target_creator,
+					"checking if sender is a room creator for initial membership event"
+				);
+				let is_creator = sender_creator && target_creator;
 
 				if is_creator {
 					debug!("sender is room creator, allowing join");
diff --git a/src/service/migrations.rs b/src/service/migrations.rs
index 4754058b..e604ebfd 100644
--- a/src/service/migrations.rs
+++ b/src/service/migrations.rs
@@ -140,7 +140,7 @@ async fn migrate(services: &Services) -> Result<()> {
 
 	if services.globals.db.database_version().await < 18 {
 		services.globals.db.bump_database_version(18);
-		info!("Migration: Bumped database version to 18")
+		info!("Migration: Bumped database version to 18");
 	}
 
 	assert_eq!(
diff --git a/src/service/rooms/auth_chain/mod.rs b/src/service/rooms/auth_chain/mod.rs
index 7a31c946..28669848 100644
--- a/src/service/rooms/auth_chain/mod.rs
+++ b/src/service/rooms/auth_chain/mod.rs
@@ -196,7 +196,7 @@ async fn get_auth_chain_inner(
 			},
 			| Ok(pdu) => {
 				if let Some(claimed_room_id) = pdu.room_id.clone() {
-					if claimed_room_id != room_id.to_owned() {
+					if claimed_room_id != *room_id {
 						return Err!(Request(Forbidden(error!(
 							?event_id,
 							?room_id,
diff --git a/src/service/rooms/timeline/build.rs b/src/service/rooms/timeline/build.rs
index 8c34e64c..741769af 100644
--- a/src/service/rooms/timeline/build.rs
+++ b/src/service/rooms/timeline/build.rs
@@ -1,6 +1,6 @@
 use std::{collections::HashSet, iter::once};
 
-use conduwuit::{RoomVersion, trace};
+use conduwuit::trace;
 use conduwuit_core::{
 	Err, Result, implement,
 	matrix::{event::Event, pdu::PduBuilder},
@@ -12,7 +12,6 @@ use ruma::{
 	events::{
 		TimelineEventType,
 		room::{
-			create::RoomCreateEventContent,
 			member::{MembershipState, RoomMemberEventContent},
 			redaction::RoomRedactionEventContent,
 		},
@@ -25,7 +24,7 @@ use super::RoomMutexGuard;
 /// takes a roomid_mutex_state, meaning that only this function is able to
 /// mutate the room state.
 #[implement(super::Service)]
-#[tracing::instrument(skip(self, state_lock), level = "trace")]
+#[tracing::instrument(skip(self, state_lock, pdu_builder), level = "trace")]
 pub async fn build_and_append_pdu(
 	&self,
 	pdu_builder: PduBuilder,
@@ -99,16 +98,11 @@ pub async fn build_and_append_pdu(
 		}
 	}
 	if *pdu.kind() == TimelineEventType::RoomCreate {
-		trace!("Running room create checks for room {room_id}");
-		let content: RoomCreateEventContent = pdu.get_content()?;
-		let room_features = RoomVersion::new(&content.room_version)?;
-		if room_features.room_ids_as_hashes {
-			// bootstrap shortid for room
-			self.services
-				.short
-				.get_or_create_shortroomid(&room_id)
-				.await;
-		}
+		trace!("Creating shortroomid for {room_id}");
+		self.services
+			.short
+			.get_or_create_shortroomid(&room_id)
+			.await;
 	}
 
 	// We append to state before appending the pdu, so we don't have a moment in
@@ -116,6 +110,7 @@ pub async fn build_and_append_pdu(
 	// fail.
 	trace!("Appending {} state for room {room_id}", pdu.event_id());
 	let statehashid = self.services.state.append_to_state(&pdu, &room_id).await?;
+	trace!("State hash ID for {room_id}: {statehashid:?}");
 
 	trace!("Generating raw ID for PDU {}", pdu.event_id());
 	let pdu_id = self
diff --git a/src/service/rooms/timeline/create.rs b/src/service/rooms/timeline/create.rs
index c161a23a..31046680 100644
--- a/src/service/rooms/timeline/create.rs
+++ b/src/service/rooms/timeline/create.rs
@@ -57,18 +57,30 @@ pub async fn create_hash_and_sign_event(
 		timestamp,
 	} = pdu_builder;
 	// If there was no create event yet, assume we are creating a room
+	trace!(
+		"Creating event of type {} in room {}",
+		event_type,
+		room_id.as_ref().map_or("None", |id| id.as_str())
+	);
 	let room_version_id = match room_id {
-		| Some(room_id) => self
-			.services
-			.state
-			.get_room_version(room_id)
-			.await
-			.or_else(|_| from_evt(room_id.to_owned(), &event_type.clone(), &content.clone()))?,
-		| None => from_evt(
-			RoomId::new(self.services.globals.server_name()),
-			&event_type.clone(),
-			&content.clone(),
-		)?,
+		| Some(room_id) => {
+			trace!(%room_id, "Looking up existing room ID");
+			self.services
+				.state
+				.get_room_version(room_id)
+				.await
+				.or_else(|_| {
+					from_evt(room_id.to_owned(), &event_type.clone(), &content.clone())
+				})?
+		},
+		| None => {
+			trace!("No room ID, assuming room creation");
+			from_evt(
+				RoomId::new(self.services.globals.server_name()),
+				&event_type.clone(),
+				&content.clone(),
+			)?
+		},
 	};
 
 	let room_version = RoomVersion::new(&room_version_id).expect("room version is supported");