diff --git a/schemata/config-v1.json b/schemata/config-v1.json
index bf5b358..68eff9f 100644
--- a/schemata/config-v1.json
+++ b/schemata/config-v1.json
@@ -5,6 +5,9 @@
 				"kind": {
 					"const": "cocoa",
 					"default": "cocoa",
+					"enum": [
+						"cocoa"
+					],
 					"title": "Kind",
 					"type": "string"
 				}
@@ -49,14 +52,28 @@
 		"WebsocketsReceiverConfig": {
 			"properties": {
 				"host": {
+					"anyOf": [
+						{
+							"format": "hostname",
+							"type": "string"
+						},
+						{
+							"items": {
+								"format": "hostname",
+								"type": "string"
+							},
+							"type": "array"
+						}
+					],
 					"description": "The hostname you'd like your WebSockets server to listen on. In most cases the default behaviour, which binds to all network interfaces, will be fine.",
-					"format": "hostname",
-					"title": "Host",
-					"type": "string"
+					"title": "Host"
 				},
 				"kind": {
 					"const": "websockets",
 					"default": "websockets",
+					"enum": [
+						"websockets"
+					],
 					"title": "Kind",
 					"type": "string"
 				},
diff --git a/schemata/playback-v1.json b/schemata/playback-v1.json
index 7c97aa4..58b7244 100644
--- a/schemata/playback-v1.json
+++ b/schemata/playback-v1.json
@@ -104,7 +104,7 @@
 		"Queue": {
 			"properties": {
 				"current": {
-					"description": "The zero-based index of the current song in MPD's queue. If MPD is currently stopped, then there is no current song in the queue, indicated by None.",
+					"description": "The zero-based index of the current song in MPD's queue.",
 					"title": "Current",
 					"type": "integer"
 				},
@@ -136,6 +136,9 @@
 						},
 						{
 							"const": "oneshot",
+							"enum": [
+								"oneshot"
+							],
 							"type": "string"
 						}
 					],
@@ -169,6 +172,9 @@
 						},
 						{
 							"const": "oneshot",
+							"enum": [
+								"oneshot"
+							],
 							"type": "string"
 						}
 					],
@@ -322,6 +328,9 @@
 				"state": {
 					"const": "stop",
 					"default": "stop",
+					"enum": [
+						"stop"
+					],
 					"title": "State",
 					"type": "string"
 				}
diff --git a/src/mpd_now_playable/config/model.py b/src/mpd_now_playable/config/model.py
index a112042..0fde2d1 100644
--- a/src/mpd_now_playable/config/model.py
+++ b/src/mpd_now_playable/config/model.py
@@ -35,7 +35,7 @@ class WebsocketsReceiverConfig(BaseReceiverConfig):
 	#: The hostname you'd like your WebSockets server to listen on. In most
 	#: cases the default behaviour, which binds to all network interfaces, will
 	#: be fine.
-	host: Optional[Host] = None
+	host: Optional[Host | tuple[Host, ...]] = None
 
 
 ReceiverConfig = Annotated[
diff --git a/src/mpd_now_playable/mpd/convert/to_playback.py b/src/mpd_now_playable/mpd/convert/to_playback.py
index 77adfa2..29b2223 100644
--- a/src/mpd_now_playable/mpd/convert/to_playback.py
+++ b/src/mpd_now_playable/mpd/convert/to_playback.py
@@ -9,8 +9,8 @@ from .to_song import to_song
 
 def to_queue(mpd: MpdState) -> Queue:
 	return Queue(
-		current=option_fmap(int, mpd.current.get("pos")),
-		next=int(mpd.status.get("nextsong", 0)),
+		current=int(mpd.current["pos"]),
+		next=int(mpd.status["nextsong"]),
 		length=int(mpd.status["playlistlength"]),
 	)
 
diff --git a/src/mpd_now_playable/playback/queue.py b/src/mpd_now_playable/playback/queue.py
index df5e76c..7c93741 100644
--- a/src/mpd_now_playable/playback/queue.py
+++ b/src/mpd_now_playable/playback/queue.py
@@ -3,10 +3,8 @@ from dataclasses import dataclass
 
 @dataclass(slots=True)
 class Queue:
-	#: The zero-based index of the current song in MPD's queue. If MPD is
-	#: currently stopped, then there is no current song in the queue, indicated
-	#: by None.
-	current: int | None
+	#: The zero-based index of the current song in MPD's queue.
+	current: int
 	#: The index of the next song to be played, taking into account random and
 	#: repeat playback settings.
 	next: int
diff --git a/src/mpd_now_playable/receivers/cocoa/convert/to_nsimage.py b/src/mpd_now_playable/receivers/cocoa/convert/to_nsimage.py
index e8544ed..213914d 100644
--- a/src/mpd_now_playable/receivers/cocoa/convert/to_nsimage.py
+++ b/src/mpd_now_playable/receivers/cocoa/convert/to_nsimage.py
@@ -37,4 +37,4 @@ def ns_image_to_media_item_artwork(img: NSImage) -> MPMediaItemArtwork:
 	)
 
 
-MPD_LOGO = ns_image_to_media_item_artwork(logo_to_ns_image())
+MPD_LOGO = logo_to_ns_image()
diff --git a/src/mpd_now_playable/receivers/cocoa/now_playing.py b/src/mpd_now_playable/receivers/cocoa/now_playing.py
index 83ba472..602006a 100644
--- a/src/mpd_now_playable/receivers/cocoa/now_playing.py
+++ b/src/mpd_now_playable/receivers/cocoa/now_playing.py
@@ -1,7 +1,7 @@
 from collections.abc import Callable, Coroutine
 from typing import Literal
 
-from AppKit import NSApplication, NSApplicationActivationPolicyAccessory
+from corefoundationasyncio import CoreFoundationEventLoop
 from MediaPlayer import (
 	MPChangePlaybackPositionCommandEvent,
 	MPMusicPlaybackStatePlaying,
@@ -12,8 +12,6 @@ from MediaPlayer import (
 	MPRemoteCommandHandlerStatusSuccess,
 )
 
-from corefoundationasyncio import CoreFoundationEventLoop
-
 from ...config.model import CocoaReceiverConfig
 from ...playback import Playback
 from ...playback.state import PlaybackState
@@ -43,9 +41,6 @@ class CocoaNowPlayingReceiver(Receiver):
 		pass
 
 	async def start(self, player: Player) -> None:
-		NSApplication.sharedApplication().setActivationPolicy_(
-			NSApplicationActivationPolicyAccessory
-		)
 		self.cmd_center = MPRemoteCommandCenter.sharedCommandCenter()
 		self.info_center = MPNowPlayingInfoCenter.defaultCenter()
 
diff --git a/src/mpd_now_playable/receivers/websockets/receiver.py b/src/mpd_now_playable/receivers/websockets/receiver.py
index d218f35..a125b6b 100644
--- a/src/mpd_now_playable/receivers/websockets/receiver.py
+++ b/src/mpd_now_playable/receivers/websockets/receiver.py
@@ -2,7 +2,7 @@ from pathlib import Path
 
 import ormsgpack
 from websockets import broadcast
-from websockets.asyncio.server import Server, ServerConnection, serve
+from websockets.server import WebSocketServerProtocol, serve
 from yarl import URL
 
 from ...config.model import WebsocketsReceiverConfig
@@ -24,11 +24,12 @@ def default(value: object) -> object:
 class WebsocketsReceiver(Receiver):
 	config: WebsocketsReceiverConfig
 	player: Player
-	server: Server
+	connections: set[WebSocketServerProtocol]
 	last_status: bytes = MSGPACK_NULL
 
 	def __init__(self, config: WebsocketsReceiverConfig):
 		self.config = config
+		self.connections = set()
 
 	@classmethod
 	def loop_factory(cls) -> DefaultLoopFactory:
@@ -36,14 +37,18 @@ class WebsocketsReceiver(Receiver):
 
 	async def start(self, player: Player) -> None:
 		self.player = player
-		self.server = await serve(
+		await serve(
 			self.handle, host=self.config.host, port=self.config.port, reuse_port=True
 		)
 
-	async def handle(self, conn: ServerConnection) -> None:
+	async def handle(self, conn: WebSocketServerProtocol) -> None:
+		self.connections.add(conn)
 		await conn.send(self.last_status)
-		await conn.wait_closed()
+		try:
+			await conn.wait_closed()
+		finally:
+			self.connections.remove(conn)
 
 	async def update(self, playback: Playback) -> None:
 		self.last_status = ormsgpack.packb(playback, default=default)
-		broadcast(self.server.connections, self.last_status)
+		broadcast(self.connections, self.last_status)
diff --git a/stubs/AppKit/__init__.pyi b/stubs/AppKit/__init__.pyi
index 50b8fcc..30512c2 100644
--- a/stubs/AppKit/__init__.pyi
+++ b/stubs/AppKit/__init__.pyi
@@ -2,42 +2,32 @@ from typing import Final, Literal
 
 from Foundation import CGSize
 
-NSApplicationActivationPolicyRegular: Final = 0
-NSApplicationActivationPolicyAccessory: Final = 1
-NSApplicationActivationPolicyProhibited: Final = 2
-NSApplicationActivationPolicy = Literal[0, 1, 2]
-
-class NSApplication:
-	@staticmethod
-	def sharedApplication() -> NSApplication: ...
-	def setActivationPolicy_(self, policy: NSApplicationActivationPolicy) -> bool: ...
-
 # There are many other operations available but we only actually use copy, so we don't need all of them here.
 NSCompositingOperationClear: Final = 0
 NSCompositingOperationCopy: Final = 1
 NSCompositingOperation = Literal[0, 1]
 
 class NSRect:
-	pass
+    pass
 
 def NSMakeRect(x: float, y: float, w: float, h: float) -> NSRect: ...
 
 class NSImage:
-	@staticmethod
-	def alloc() -> type[NSImage]: ...
-	@staticmethod
-	def initByReferencingFile_(file: str) -> NSImage: ...
-	@staticmethod
-	def initWithData_(data: bytes) -> NSImage: ...
-	@staticmethod
-	def initWithSize_(size: CGSize) -> NSImage: ...
-	def size(self) -> CGSize: ...
-	def lockFocus(self) -> None: ...
-	def unlockFocus(self) -> None: ...
-	def drawInRect_fromRect_operation_fraction_(
-		self,
-		inRect: NSRect,
-		fromRect: NSRect,
-		operation: NSCompositingOperation,
-		fraction: float,
-	) -> None: ...
+    @staticmethod
+    def alloc() -> type[NSImage]: ...
+
+    @staticmethod
+    def initByReferencingFile_(file: str) -> NSImage: ...
+
+    @staticmethod
+    def initWithData_(data: bytes) -> NSImage: ...
+
+    @staticmethod
+    def initWithSize_(size: CGSize) -> NSImage: ...
+
+    def size(self) -> CGSize: ...
+
+    def lockFocus(self) -> None: ...
+    def unlockFocus(self) -> None: ...
+
+    def drawInRect_fromRect_operation_fraction_(self, inRect: NSRect, fromRect: NSRect, operation: NSCompositingOperation, fraction: float) -> None: ...