Index: src/OFHTTPClient.h
==================================================================
--- src/OFHTTPClient.h
+++ src/OFHTTPClient.h
@@ -21,11 +21,10 @@
 #endif
 
 OF_ASSUME_NONNULL_BEGIN
 
 @class OFDictionary OF_GENERIC(KeyType, ObjectType);
-@class OFException;
 @class OFHTTPClient;
 @class OFHTTPRequest;
 @class OFHTTPResponse;
 @class OFTCPSocket;
 @class OFURL;

Index: src/OFHTTPClient.m
==================================================================
--- src/OFHTTPClient.m
+++ src/OFHTTPClient.m
@@ -564,11 +564,11 @@
 				context: nil];
 }
 
 - (void)socketDidConnect: (OFTCPSocket *)socket
 		 context: (id)context
-	       exception: (OFException *)exception
+	       exception: (id)exception
 {
 	if ([_client->_delegate respondsToSelector:
 	    @selector(client:didCreateSocket:forRequest:)])
 		[_client->_delegate client: _client
 			   didCreateSocket: socket

Index: src/OFHTTPServer.h
==================================================================
--- src/OFHTTPServer.h
+++ src/OFHTTPServer.h
@@ -24,11 +24,10 @@
 
 @class OFHTTPServer;
 @class OFHTTPRequest;
 @class OFHTTPResponse;
 @class OFTCPSocket;
-@class OFException;
 
 /*!
  * @protocol OFHTTPServerDelegate OFHTTPServer.h ObjFW/OFHTTPServer.h
  *
  * @brief A delegate for OFHTTPServer.
@@ -57,11 +56,11 @@
  * @return Whether to continue listening. If you return false, existing
  *	   connections will still be handled and you can start accepting new
  *	   connections again by calling @ref OFHTTPServer::start again.
  */
 -			  (bool)server: (OFHTTPServer *)server
-  didReceiveExceptionOnListeningSocket: (OFException *)exception;
+  didReceiveExceptionOnListeningSocket: (id)exception;
 
 /*!
  * @brief This method is called when a client socket encountered an exception.
  *
  * This can happen when the OFHTTPServer tries to properly close the
@@ -76,11 +75,11 @@
  * @param exception The exception which occurred
  */
 -		    (void)server: (OFHTTPServer *)server
   didReceiveExceptionForResponse: (OFHTTPResponse *)response
 			 request: (OFHTTPRequest *)request
-		       exception: (OFException *)exception;
+		       exception: (id)exception;
 @end
 
 /*!
  * @class OFHTTPServer OFHTTPServer.h ObjFW/OFHTTPServer.h
  *

Index: src/OFHTTPServer.m
==================================================================
--- src/OFHTTPServer.m
+++ src/OFHTTPServer.m
@@ -48,11 +48,11 @@
 
 @interface OFHTTPServer ()
 - (bool)of_socket: (OFTCPSocket *)socket
   didAcceptSocket: (OFTCPSocket *)clientSocket
 	  context: (id)context
-	exception: (OFException *)exception;
+	exception: (id)exception;
 @end
 
 static const char *
 statusCodeToString(short code)
 {
@@ -342,18 +342,18 @@
 - initWithSocket: (OFTCPSocket *)socket
 	  server: (OFHTTPServer *)server;
 - (bool)socket: (OFTCPSocket *)socket
    didReadLine: (OFString *)line
        context: (id)context
-     exception: (OFException *)exception;
+     exception: (id)exception;
 - (bool)parseProlog: (OFString *)line;
 - (bool)parseHeaders: (OFString *)line;
 -      (bool)socket: (OFTCPSocket *)socket
   didReadIntoBuffer: (char *)buffer
 	     length: (size_t)length
 	    context: (id)context
-	  exception: (OFException *)exception;
+	  exception: (id)exception;
 - (bool)sendErrorAndClose: (short)statusCode;
 - (void)createResponse;
 @end
 
 @implementation OFHTTPServer_Connection
@@ -397,11 +397,11 @@
 }
 
 - (bool)socket: (OFTCPSocket *)socket
    didReadLine: (OFString *)line
        context: (id)context
-     exception: (OFException *)exception
+     exception: (id)exception
 {
 	if (line == nil || exception != nil)
 		return false;
 
 	@try {
@@ -577,11 +577,11 @@
 
 -      (bool)socket: (OFTCPSocket *)socket
   didReadIntoBuffer: (char *)buffer
 	     length: (size_t)length
 	    context: (id)context
-	  exception: (OFException *)exception
+	  exception: (id)exception
 {
 	if ([socket isAtEndOfStream] || exception != nil)
 		return false;
 
 	[_body addItems: buffer
@@ -742,11 +742,11 @@
 }
 
 - (bool)of_socket: (OFTCPSocket *)socket
   didAcceptSocket: (OFTCPSocket *)clientSocket
 	  context: (id)context
-	exception: (OFException *)exception
+	exception: (id)exception
 {
 	OFHTTPServer_Connection *connection;
 
 	if (exception != nil) {
 		if ([_delegate respondsToSelector:

Index: src/OFRunLoop.m
==================================================================
--- src/OFRunLoop.m
+++ src/OFRunLoop.m
@@ -120,28 +120,27 @@
 
 @implementation OFRunLoop_ReadQueueItem
 - (bool)handleForObject: (id)object
 {
 	size_t length;
-	OFException *exception = nil;
+	id exception = nil;
 
 	@try {
 		length = [object readIntoBuffer: _buffer
 					 length: _length];
-	} @catch (OFException *e) {
+	} @catch (id e) {
 		length = 0;
 		exception = e;
 	}
 
 # ifdef OF_HAVE_BLOCKS
 	if (_block != NULL)
 		return _block(object, _buffer, length, exception);
 	else {
 # endif
-		bool (*func)(id, SEL, OFStream *, void *, size_t, id,
-		    OFException *) = (bool (*)(id, SEL, OFStream *, void *,
-		    size_t, id, OFException *))
+		bool (*func)(id, SEL, OFStream *, void *, size_t, id, id) =
+		    (bool (*)(id, SEL, OFStream *, void *, size_t, id, id))
 		    [_target methodForSelector: _selector];
 
 		return func(_target, _selector, object, _buffer, length,
 		    _context, exception);
 # ifdef OF_HAVE_BLOCKS
@@ -161,16 +160,16 @@
 
 @implementation OFRunLoop_ExactReadQueueItem
 - (bool)handleForObject: (id)object
 {
 	size_t length;
-	OFException *exception = nil;
+	id exception = nil;
 
 	@try {
 		length = [object readIntoBuffer: (char *)_buffer + _readLength
 					 length: _exactLength - _readLength];
-	} @catch (OFException *e) {
+	} @catch (id e) {
 		length = 0;
 		exception = e;
 	}
 
 	_readLength += length;
@@ -186,13 +185,12 @@
 
 		_readLength = 0;
 		return true;
 	} else {
 # endif
-		bool (*func)(id, SEL, OFStream *, void *, size_t, id,
-		    OFException *) = (bool (*)(id, SEL, OFStream *, void *,
-		    size_t, id, OFException *))
+		bool (*func)(id, SEL, OFStream *, void *, size_t, id, id) =
+		    (bool (*)(id, SEL, OFStream *, void *, size_t, id, id))
 		    [_target methodForSelector: _selector];
 
 		if (!func(_target, _selector, object, _buffer, _readLength,
 		    _context, exception))
 			return false;
@@ -216,15 +214,15 @@
 
 @implementation OFRunLoop_ReadLineQueueItem
 - (bool)handleForObject: (id)object
 {
 	OFString *line;
-	OFException *exception = nil;
+	id exception = nil;
 
 	@try {
 		line = [object tryReadLineWithEncoding: _encoding];
-	} @catch (OFException *e) {
+	} @catch (id e) {
 		line = nil;
 		exception = e;
 	}
 
 	if (line == nil && ![object isAtEndOfStream] && exception == nil)
@@ -233,13 +231,13 @@
 # ifdef OF_HAVE_BLOCKS
 	if (_block != NULL)
 		return _block(object, line, exception);
 	else {
 # endif
-		bool (*func)(id, SEL, OFStream *, OFString *, id,
-		    OFException *) = (bool (*)(id, SEL, OFStream *, OFString *,
-		    id, OFException *))[_target methodForSelector: _selector];
+		bool (*func)(id, SEL, OFStream *, OFString *, id, id) =
+		    (bool (*)(id, SEL, OFStream *, OFString *, id, id))
+		    [_target methodForSelector: _selector];
 
 		return func(_target, _selector, object, line, _context,
 		    exception);
 # ifdef OF_HAVE_BLOCKS
 	}
@@ -258,27 +256,26 @@
 
 @implementation OFRunLoop_AcceptQueueItem
 - (bool)handleForObject: (id)object
 {
 	OFTCPSocket *newSocket;
-	OFException *exception = nil;
+	id exception = nil;
 
 	@try {
 		newSocket = [object accept];
-	} @catch (OFException *e) {
+	} @catch (id e) {
 		newSocket = nil;
 		exception = e;
 	}
 
 # ifdef OF_HAVE_BLOCKS
 	if (_block != NULL)
 		return _block(object, newSocket, exception);
 	else {
 # endif
-		bool (*func)(id, SEL, OFTCPSocket *, OFTCPSocket *, id,
-		    OFException *) = (bool (*)(id, SEL, OFTCPSocket *,
-		    OFTCPSocket *, id, OFException *))
+		bool (*func)(id, SEL, OFTCPSocket *, OFTCPSocket *, id, id) =
+		    (bool (*)(id, SEL, OFTCPSocket *, OFTCPSocket *, id, id))
 		    [_target methodForSelector: _selector];
 
 		return func(_target, _selector, object, newSocket, _context,
 		    exception);
 # ifdef OF_HAVE_BLOCKS
@@ -299,17 +296,17 @@
 @implementation OFRunLoop_UDPReceiveQueueItem
 - (bool)handleForObject: (id)object
 {
 	size_t length;
 	of_udp_socket_address_t address;
-	OFException *exception = nil;
+	id exception = nil;
 
 	@try {
 		length = [object receiveIntoBuffer: _buffer
 					    length: _length
 					    sender: &address];
-	} @catch (OFException *e) {
+	} @catch (id e) {
 		length = 0;
 		exception = e;
 	}
 
 # ifdef OF_HAVE_BLOCKS
@@ -316,13 +313,13 @@
 	if (_block != NULL)
 		return _block(object, _buffer, length, address, exception);
 	else {
 # endif
 		bool (*func)(id, SEL, OFUDPSocket *, void *, size_t,
-		    of_udp_socket_address_t address, id, OFException *) =
+		    of_udp_socket_address_t address, id, id) =
 		    (bool (*)(id, SEL, OFUDPSocket *, void *, size_t,
-		    of_udp_socket_address_t, id, OFException *))
+		    of_udp_socket_address_t, id, id))
 		    [_target methodForSelector: _selector];
 
 		return func(_target, _selector, object, _buffer, length,
 		    address, _context, exception);
 # ifdef OF_HAVE_BLOCKS

Index: src/OFStream.h
==================================================================
--- src/OFStream.h
+++ src/OFStream.h
@@ -33,11 +33,10 @@
 
 /*! @file */
 
 @class OFStream;
 @class OFData;
-@class OFException;
 
 #if defined(OF_HAVE_SOCKETS) && defined(OF_HAVE_BLOCKS)
 /*!
  * @brief A block which is called when data was read from the stream.
  *
@@ -47,11 +46,11 @@
  * @param exception An exception which occurred while reading or `nil` on
  *		    success
  * @return A bool whether the same block should be used for the next read
  */
 typedef bool (^of_stream_async_read_block_t)(OFStream *stream, void *buffer,
-    size_t length, OFException *_Nullable exception);
+    size_t length, id _Nullable exception);
 
 /*!
  * @brief A block which is called when a line was read from the stream.
  *
  * @param stream The stream on which a line was read
@@ -60,11 +59,11 @@
  * @param exception An exception which occurred while reading or `nil` on
  *		    success
  * @return A bool whether the same block should be used for the next read
  */
 typedef bool (^of_stream_async_read_line_block_t)(OFStream *stream,
-    OFString *_Nullable line, OFException *_Nullable exception);
+    OFString *_Nullable line, id _Nullable exception);
 #endif
 
 /*!
  * @class OFStream OFStream.h ObjFW/OFStream.h
  *
@@ -167,11 +166,11 @@
  *		 data has been received. If you want the next method in the
  *		 queue to handle the data received next, you need to return
  *		 false from the method.
  * @param selector The selector to call on the target. The signature must be
  *		   `bool (OFStream *stream, void *buffer, size_t length,
- *		   id context, OFException *exception)`.
+ *		   id context, id exception)`.
  */
 - (void)asyncReadIntoBuffer: (void *)buffer
 		     length: (size_t)length
 		     target: (id)target
 		   selector: (SEL)selector
@@ -198,11 +197,11 @@
  *		 data has been received. If you want the next method in the
  *		 queue to handle the data received next, you need to return
  *		 false from the method.
  * @param selector The selector to call on the target. The signature must be
  *		   `bool (OFStream *stream, void *buffer, size_t size,
- *		   id context, OFException *exception)`.
+ *		   id context, id exception)`.
  */
 - (void)asyncReadIntoBuffer: (void *)buffer
 		exactLength: (size_t)length
 		     target: (id)target
 		   selector: (SEL)selector
@@ -622,11 +621,11 @@
  *		 again when the next line has been received. If you want the
  *		 next method in the queue to handle the next line, you need to
  *		 return false from the method
  * @param selector The selector to call on the target. The signature must be
  *		   `bool (OFStream *stream, OFString *line, id context,
- *		   OFException *exception)`.
+ *		   id exception)`.
  */
 - (void)asyncReadLineWithTarget: (id)target
 		       selector: (SEL)selector
 			context: (nullable id)context;
 
@@ -642,12 +641,12 @@
  *		 been received. If the method returns true, it will be called
  *		 again when the next line has been received. If you want the
  *		 next method in the queue to handle the next line, you need to
  *		 return false from the method
  * @param selector The selector to call on the target. The signature must be
- *		   `bool (OFStream *stream, OFString *line,
- *		   id context, OFException *exception)`.
+ *		   `bool (OFStream *stream, OFString *line, id context,
+ *		   id exception)`.
  */
 - (void)asyncReadLineWithEncoding: (of_string_encoding_t)encoding
 			   target: (id)target
 			 selector: (SEL)selector
 			  context: (nullable id)context;
@@ -773,11 +772,11 @@
 - (void)flushWriteBuffer;
 
 /*!
  * @brief Writes from a buffer into the stream.
  *
- * @param buffer The buffer from which the data is written to the stream
+ * @param buffer The buffer from which the data is written into the stream
  * @param length The length of the data that should be written
  */
 - (void)writeBuffer: (const void *)buffer
 	     length: (size_t)length;
 

Index: src/OFTCPSocket.h
==================================================================
--- src/OFTCPSocket.h
+++ src/OFTCPSocket.h
@@ -32,11 +32,11 @@
  * @param socket The socket which connected
  * @param exception An exception which occurred while connecting the socket or
  *		    `nil` on success
  */
 typedef void (^of_tcp_socket_async_connect_block_t)(OFTCPSocket *socket,
-    OFException *_Nullable exception);
+    id _Nullable exception);
 
 /*!
  * @brief A block which is called when the socket accepted a connection.
  *
  * @param socket The socket which accepted the connection
@@ -45,11 +45,11 @@
  *		    `nil` on success
  * @return A bool whether the same block should be used for the next incoming
  *	   connection
  */
 typedef bool (^of_tcp_socket_async_accept_block_t)(OFTCPSocket *socket,
-    OFTCPSocket *acceptedSocket, OFException *_Nullable exception);
+    OFTCPSocket *acceptedSocket, id _Nullable exception);
 #endif
 
 /*!
  * @class OFTCPSocket OFTCPSocket.h ObjFW/OFTCPSocket.h
  *
@@ -125,12 +125,11 @@
  * @param host The host to connect to
  * @param port The port on the host to connect to
  * @param target The target on which to call the selector once the connection
  *		 has been established
  * @param selector The selector to call on the target. The signature must be
- *		   `void (OFTCPSocket *socket, id context,
- *		   OFException *exception)`.
+ *		   `void (OFTCPSocket *socket, id context, id exception)`.
  */
 - (void)asyncConnectToHost: (OFString *)host
 		      port: (uint16_t)port
 		    target: (id)target
 		  selector: (SEL)selector
@@ -188,11 +187,11 @@
  *		 connection has been accepted. The method returns whether the
  *		 next incoming connection should be accepted by the specified
  *		 block as well.
  * @param selector The selector to call on the target. The signature must be
  *		   `bool (OFTCPSocket *socket, OFTCPSocket *acceptedSocket,
- *		   id context, OFException *exception)`.
+ *		   id context, id exception)`.
  */
 - (void)asyncAcceptWithTarget: (id)target
 		     selector: (SEL)selector
 		      context: (nullable id)context;
 

Index: src/OFTCPSocket.m
==================================================================
--- src/OFTCPSocket.m
+++ src/OFTCPSocket.m
@@ -76,11 +76,11 @@
 	SEL _selector;
 	id _context;
 # ifdef OF_HAVE_BLOCKS
 	of_tcp_socket_async_connect_block_t _block;
 # endif
-	OFException *_exception;
+	id _exception;
 }
 
 - initWithSourceThread: (OFThread *)sourceThread
 		socket: (OFTCPSocket *)socket
 		  host: (OFString *)host
@@ -170,12 +170,12 @@
 # ifdef OF_HAVE_BLOCKS
 	if (_block != NULL)
 		_block(_socket, _exception);
 	else {
 # endif
-		void (*func)(id, SEL, OFTCPSocket *, id, OFException *) =
-		    (void (*)(id, SEL, OFTCPSocket *, id, OFException *))
+		void (*func)(id, SEL, OFTCPSocket *, id, id) =
+		    (void (*)(id, SEL, OFTCPSocket *, id, id))
 		    [_target methodForSelector: _selector];
 
 		func(_target, _selector, _socket, _context, _exception);
 # ifdef OF_HAVE_BLOCKS
 	}
@@ -187,11 +187,11 @@
 	void *pool = objc_autoreleasePoolPush();
 
 	@try {
 		[_socket connectToHost: _host
 				  port: _port];
-	} @catch (OFException *e) {
+	} @catch (id e) {
 		_exception = [e retain];
 	}
 
 	[self performSelector: @selector(didConnect)
 		     onThread: _sourceThread

Index: src/OFUDPSocket.h
==================================================================
--- src/OFUDPSocket.h
+++ src/OFUDPSocket.h
@@ -22,11 +22,10 @@
 OF_ASSUME_NONNULL_BEGIN
 
 /*! @file */
 
 @class OFUDPSocket;
-@class OFException;
 
 /*!
  * @struct of_udp_socket_address_t OFUDPSocket.h ObjFW/OFUDPSocket.h
  *
  * @brief A struct which represents a host / port pair for a UDP socket.
@@ -46,12 +45,11 @@
  * @param address The address of the resolved host / port pair
  * @param exception An exception which occurred while resolving or `nil` on
  *		    success
  */
 typedef void (^of_udp_socket_async_resolve_block_t)(OFString *host,
-    uint16_t port, of_udp_socket_address_t address,
-    OFException *_Nullable exception);
+    uint16_t port, of_udp_socket_address_t address, id _Nullable exception);
 
 /*!
  * @brief A block which is called when a packet has been received.
  *
  * @param socket The UDP which received a packet
@@ -62,11 +60,11 @@
  *		    success
  * @return A bool whether the same block should be used for the next receive
  */
 typedef bool (^of_udp_socket_async_receive_block_t)(OFUDPSocket *socket,
     void *buffer, size_t length, of_udp_socket_address_t sender,
-    OFException *_Nullable exception);
+    id _Nullable exception);
 #endif
 
 /*!
  * @class OFUDPSocket OFUDPSocket.h ObjFW/OFUDPSocket.h
  *
@@ -125,12 +123,11 @@
  * @param port The port for the resulting address
  * @param target The target on which to call the selector once the host has been
  *		 resolved
  * @param selector The selector to call on the target. The signature must be
  *		   `void (OFString *host, uint16_t port,
- *		   of_udp_socket_address_t address, id context,
- *		   OFException *exception)`.
+ *		   of_udp_socket_address_t address, id context, id exception)`.
  */
 + (void)asyncResolveAddressForHost: (OFString *)host
 			      port: (uint16_t)port
 			    target: (id)target
 			  selector: (SEL)selector
@@ -205,12 +202,11 @@
  *		 when more datagrams have been received. If you want the next
  *		 method in the queue to handle the datagram received next, you
  *		 need to return false from the method.
  * @param selector The selector to call on the target. The signature must be
  *		   `bool (OFUDPSocket *socket, void *buffer, size_t length,
- *		   of_udp_socket_address_t, id context,
- *		   OFException *exception)`.
+ *		   of_udp_socket_address_t, id context, id exception)`.
  */
 - (void)asyncReceiveIntoBuffer: (void *)buffer
 			length: (size_t)length
 			target: (id)target
 		      selector: (SEL)selector

Index: src/OFUDPSocket.m
==================================================================
--- src/OFUDPSocket.m
+++ src/OFUDPSocket.m
@@ -54,11 +54,11 @@
 	id _context;
 # ifdef OF_HAVE_BLOCKS
 	of_udp_socket_async_resolve_block_t _block;
 # endif
 	of_udp_socket_address_t _address;
-	OFException *_exception;
+	id _exception;
 }
 
 - initWithSourceThread: (OFThread *)sourceThread
 		  host: (OFString *)host
 		  port: (uint16_t)port
@@ -142,13 +142,13 @@
 	if (_block != NULL)
 		_block(_host, _port, _address, _exception);
 	else {
 # endif
 		void (*func)(id, SEL, OFString *, uint16_t,
-		    of_udp_socket_address_t, id, OFException *) =
+		    of_udp_socket_address_t, id, id) =
 		    (void (*)(id, SEL, OFString *, uint16_t,
-		    of_udp_socket_address_t, id, OFException *))
+		    of_udp_socket_address_t, id, id))
 		    [_target methodForSelector: _selector];
 
 		func(_target, _selector, _host, _port, _address, _context,
 		    _exception);
 # ifdef OF_HAVE_BLOCKS
@@ -162,11 +162,11 @@
 
 	@try {
 		[OFUDPSocket resolveAddressForHost: _host
 					      port: _port
 					   address: &_address];
-	} @catch (OFException *e) {
+	} @catch (id e) {
 		_exception = e;
 	}
 
 	[self performSelector: @selector(didResolve)
 		     onThread: _sourceThread