diff --git a/dial.go b/dial.go
index ac32e62..940552c 100644
--- a/dial.go
+++ b/dial.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // TINYGO: Omit DualStack support
 // TINYGO: Omit Fast Fallback support
diff --git a/http/client.go b/http/client.go
index 8bfef71..2863c83 100644
--- a/http/client.go
+++ b/http/client.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/clone.go b/http/clone.go
index aa42a7e..4980b8d 100644
--- a/http/clone.go
+++ b/http/clone.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/cookie.go b/http/cookie.go
index 24c938c..70e1eb3 100644
--- a/http/cookie.go
+++ b/http/cookie.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/fs.go b/http/fs.go
index 3967045..6796917 100644
--- a/http/fs.go
+++ b/http/fs.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -11,6 +11,7 @@ package http
 import (
 	"errors"
 	"fmt"
+	"internal/safefilepath"
 	"io"
 	"io/fs"
 	"mime"
@@ -71,14 +72,15 @@ func mapOpenError(originalErr error, name string, sep rune, stat func(string) (f
 // Open implements FileSystem using os.Open, opening files for reading rooted
 // and relative to the directory d.
 func (d Dir) Open(name string) (File, error) {
-	if filepath.Separator != '/' && strings.ContainsRune(name, filepath.Separator) {
-		return nil, errors.New("http: invalid character in file path")
+	path, err := safefilepath.FromFS(path.Clean("/" + name))
+	if err != nil {
+		return nil, errors.New("http: invalid or unsafe file path")
 	}
 	dir := string(d)
 	if dir == "" {
 		dir = "."
 	}
-	fullName := filepath.Join(dir, filepath.FromSlash(path.Clean("/"+name)))
+	fullName := filepath.Join(dir, path)
 	f, err := os.Open(fullName)
 	if err != nil {
 		return nil, mapOpenError(err, fullName, filepath.Separator, os.Stat)
@@ -256,81 +258,95 @@ func serveContent(w ResponseWriter, r *Request, name string, modtime time.Time,
 		Error(w, err.Error(), StatusInternalServerError)
 		return
 	}
+	if size < 0 {
+		// Should never happen but just to be sure
+		Error(w, "negative content size computed", StatusInternalServerError)
+		return
+	}
 
 	// handle Content-Range header.
 	sendSize := size
 	var sendContent io.Reader = content
-	if size >= 0 {
-		ranges, err := parseRange(rangeReq, size)
-		if err != nil {
-			if err == errNoOverlap {
-				w.Header().Set("Content-Range", fmt.Sprintf("bytes */%d", size))
-			}
+	ranges, err := parseRange(rangeReq, size)
+	switch err {
+	case nil:
+	case errNoOverlap:
+		if size == 0 {
+			// Some clients add a Range header to all requests to
+			// limit the size of the response. If the file is empty,
+			// ignore the range header and respond with a 200 rather
+			// than a 416.
+			ranges = nil
+			break
+		}
+		w.Header().Set("Content-Range", fmt.Sprintf("bytes */%d", size))
+		fallthrough
+	default:
+		Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
+		return
+	}
+
+	if sumRangesSize(ranges) > size {
+		// The total number of bytes in all the ranges
+		// is larger than the size of the file by
+		// itself, so this is probably an attack, or a
+		// dumb client. Ignore the range request.
+		ranges = nil
+	}
+	switch {
+	case len(ranges) == 1:
+		// RFC 7233, Section 4.1:
+		// "If a single part is being transferred, the server
+		// generating the 206 response MUST generate a
+		// Content-Range header field, describing what range
+		// of the selected representation is enclosed, and a
+		// payload consisting of the range.
+		// ...
+		// A server MUST NOT generate a multipart response to
+		// a request for a single range, since a client that
+		// does not request multiple parts might not support
+		// multipart responses."
+		ra := ranges[0]
+		if _, err := content.Seek(ra.start, io.SeekStart); err != nil {
 			Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
 			return
 		}
-		if sumRangesSize(ranges) > size {
-			// The total number of bytes in all the ranges
-			// is larger than the size of the file by
-			// itself, so this is probably an attack, or a
-			// dumb client. Ignore the range request.
-			ranges = nil
-		}
-		switch {
-		case len(ranges) == 1:
-			// RFC 7233, Section 4.1:
-			// "If a single part is being transferred, the server
-			// generating the 206 response MUST generate a
-			// Content-Range header field, describing what range
-			// of the selected representation is enclosed, and a
-			// payload consisting of the range.
-			// ...
-			// A server MUST NOT generate a multipart response to
-			// a request for a single range, since a client that
-			// does not request multiple parts might not support
-			// multipart responses."
-			ra := ranges[0]
-			if _, err := content.Seek(ra.start, io.SeekStart); err != nil {
-				Error(w, err.Error(), StatusRequestedRangeNotSatisfiable)
-				return
-			}
-			sendSize = ra.length
-			code = StatusPartialContent
-			w.Header().Set("Content-Range", ra.contentRange(size))
-		case len(ranges) > 1:
-			sendSize = rangesMIMESize(ranges, ctype, size)
-			code = StatusPartialContent
+		sendSize = ra.length
+		code = StatusPartialContent
+		w.Header().Set("Content-Range", ra.contentRange(size))
+	case len(ranges) > 1:
+		sendSize = rangesMIMESize(ranges, ctype, size)
+		code = StatusPartialContent
 
-			pr, pw := io.Pipe()
-			mw := multipart.NewWriter(pw)
-			w.Header().Set("Content-Type", "multipart/byteranges; boundary="+mw.Boundary())
-			sendContent = pr
-			defer pr.Close() // cause writing goroutine to fail and exit if CopyN doesn't finish.
-			go func() {
-				for _, ra := range ranges {
-					part, err := mw.CreatePart(ra.mimeHeader(ctype, size))
-					if err != nil {
-						pw.CloseWithError(err)
-						return
-					}
-					if _, err := content.Seek(ra.start, io.SeekStart); err != nil {
-						pw.CloseWithError(err)
-						return
-					}
-					if _, err := io.CopyN(part, content, ra.length); err != nil {
-						pw.CloseWithError(err)
-						return
-					}
+		pr, pw := io.Pipe()
+		mw := multipart.NewWriter(pw)
+		w.Header().Set("Content-Type", "multipart/byteranges; boundary="+mw.Boundary())
+		sendContent = pr
+		defer pr.Close() // cause writing goroutine to fail and exit if CopyN doesn't finish.
+		go func() {
+			for _, ra := range ranges {
+				part, err := mw.CreatePart(ra.mimeHeader(ctype, size))
+				if err != nil {
+					pw.CloseWithError(err)
+					return
 				}
-				mw.Close()
-				pw.Close()
-			}()
-		}
+				if _, err := content.Seek(ra.start, io.SeekStart); err != nil {
+					pw.CloseWithError(err)
+					return
+				}
+				if _, err := io.CopyN(part, content, ra.length); err != nil {
+					pw.CloseWithError(err)
+					return
+				}
+			}
+			mw.Close()
+			pw.Close()
+		}()
+	}
 
-		w.Header().Set("Accept-Ranges", "bytes")
-		if w.Header().Get("Content-Encoding") == "" {
-			w.Header().Set("Content-Length", strconv.FormatInt(sendSize, 10))
-		}
+	w.Header().Set("Accept-Ranges", "bytes")
+	if w.Header().Get("Content-Encoding") == "" {
+		w.Header().Set("Content-Length", strconv.FormatInt(sendSize, 10))
 	}
 
 	w.WriteHeader(code)
@@ -433,7 +449,7 @@ func checkIfUnmodifiedSince(r *Request, modtime time.Time) condResult {
 	// The Last-Modified header truncates sub-second precision so
 	// the modtime needs to be truncated too.
 	modtime = modtime.Truncate(time.Second)
-	if modtime.Before(t) || modtime.Equal(t) {
+	if ret := modtime.Compare(t); ret <= 0 {
 		return condTrue
 	}
 	return condFalse
@@ -484,7 +500,7 @@ func checkIfModifiedSince(r *Request, modtime time.Time) condResult {
 	// The Last-Modified header truncates sub-second precision so
 	// the modtime needs to be truncated too.
 	modtime = modtime.Truncate(time.Second)
-	if modtime.Before(t) || modtime.Equal(t) {
+	if ret := modtime.Compare(t); ret <= 0 {
 		return condFalse
 	}
 	return condTrue
@@ -644,7 +660,6 @@ func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirec
 			defer ff.Close()
 			dd, err := ff.Stat()
 			if err == nil {
-				name = index
 				d = dd
 				f = ff
 			}
@@ -820,6 +835,7 @@ func (f ioFile) Readdir(count int) ([]fs.FileInfo, error) {
 
 // FS converts fsys to a FileSystem implementation,
 // for use with FileServer and NewFileTransport.
+// The files provided by fsys must implement io.Seeker.
 func FS(fsys fs.FS) FileSystem {
 	return ioFS{fsys}
 }
diff --git a/http/header.go b/http/header.go
index a5779f6..ac3d0bb 100644
--- a/http/header.go
+++ b/http/header.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // TINYGO: Removed trace stuff
 
diff --git a/http/http.go b/http/http.go
index fc1db57..900d5a9 100644
--- a/http/http.go
+++ b/http/http.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2016 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/internal/ascii/print.go b/http/internal/ascii/print.go
index c2b3a9b..b71ed91 100644
--- a/http/internal/ascii/print.go
+++ b/http/internal/ascii/print.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/internal/ascii/print_test.go b/http/internal/ascii/print_test.go
index 0b7767c..fb84a2e 100644
--- a/http/internal/ascii/print_test.go
+++ b/http/internal/ascii/print_test.go
@@ -1,3 +1,5 @@
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
+
 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
diff --git a/http/internal/chunked.go b/http/internal/chunked.go
index 34b5331..f363820 100644
--- a/http/internal/chunked.go
+++ b/http/internal/chunked.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/internal/chunked_test.go b/http/internal/chunked_test.go
index 5e29a78..002e74d 100644
--- a/http/internal/chunked_test.go
+++ b/http/internal/chunked_test.go
@@ -1,3 +1,5 @@
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
+
 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
diff --git a/http/jar.go b/http/jar.go
index 3091c58..6be849e 100644
--- a/http/jar.go
+++ b/http/jar.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/method.go b/http/method.go
index b8a4c33..5b09e98 100644
--- a/http/method.go
+++ b/http/method.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2015 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/request.go b/http/request.go
index 1971ec4..897918a 100644
--- a/http/request.go
+++ b/http/request.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // TINYGO: Removed multipart stuff
 // TINYGO: Removed trace stuff
@@ -51,9 +51,12 @@ type ProtocolError struct {
 func (pe *ProtocolError) Error() string { return pe.ErrorString }
 
 var (
-	// ErrNotSupported is returned by the Push method of Pusher
-	// implementations to indicate that HTTP/2 Push support is not
-	// available.
+	// ErrNotSupported indicates that a feature is not supported.
+	//
+	// It is returned by ResponseController methods to indicate that
+	// the handler does not support the method, and by the Push method
+	// of Pusher implementations to indicate that HTTP/2 Push support
+	// is not available.
 	ErrNotSupported = &ProtocolError{"feature not supported"}
 
 	// Deprecated: ErrUnexpectedTrailer is no longer returned by
@@ -319,7 +322,7 @@ type Request struct {
 	Response *Response
 
 	// ctx is either the client or server context. It should only
-	// be modified via copying the whole Request using WithContext.
+	// be modified via copying the whole Request using Clone or WithContext.
 	// It is unexported to prevent people from using Context wrong
 	// and mutating the contexts held by callers of the same request.
 	ctx context.Context
@@ -330,7 +333,7 @@ type Request struct {
 }
 
 // Context returns the request's context. To change the context, use
-// WithContext.
+// Clone or WithContext.
 //
 // The returned context is always non-nil; it defaults to the
 // background context.
@@ -355,9 +358,7 @@ func (r *Request) Context() context.Context {
 // sending the request, and reading the response headers and body.
 //
 // To create a new request with a context, use NewRequestWithContext.
-// To change the context of a request, such as an incoming request you
-// want to modify before sending back out, use Request.Clone. Between
-// those two uses, it's rare to need WithContext.
+// To make a deep copy of a request with a new context, use Request.Clone.
 func (r *Request) WithContext(ctx context.Context) *Request {
 	if ctx == nil {
 		panic("nil context")
@@ -424,6 +425,9 @@ var ErrNoCookie = errors.New("http: named cookie not present")
 // If multiple cookies match the given name, only one cookie will
 // be returned.
 func (r *Request) Cookie(name string) (*Cookie, error) {
+	if name == "" {
+		return nil, ErrNoCookie
+	}
 	for _, c := range readCookies(r.Header, name) {
 		return c, nil
 	}
@@ -993,6 +997,8 @@ func ReadRequest(b *bufio.Reader) (*Request, error) {
 
 func readRequest(b *bufio.Reader) (req *Request, err error) {
 	tp := newTextprotoReader(b)
+	defer putTextprotoReader(tp)
+
 	req = new(Request)
 
 	// First line: GET /index.html HTTP/1.0
@@ -1001,7 +1007,6 @@ func readRequest(b *bufio.Reader) (req *Request, err error) {
 		return nil, err
 	}
 	defer func() {
-		putTextprotoReader(tp)
 		if err == io.EOF {
 			err = io.ErrUnexpectedEOF
 		}
@@ -1132,7 +1137,8 @@ func (l *maxBytesReader) Read(p []byte) (n int, err error) {
 	// If they asked for a 32KB byte read but only 5 bytes are
 	// remaining, no need to read 32KB. 6 bytes will answer the
 	// question of the whether we hit the limit or go past it.
-	if int64(len(p)) > l.n+1 {
+	// 0 < len(p) < 2^63
+	if int64(len(p))-1 > l.n {
 		p = p[:l.n+1]
 	}
 	n, err = l.r.Read(p)
diff --git a/http/response.go b/http/response.go
index 980329f..30ffe7e 100644
--- a/http/response.go
+++ b/http/response.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // TINYGO: Removed TLS connection state
 // TINYGO: Added onEOF hook to get callback when response has been read
diff --git a/http/server.go b/http/server.go
index 1a4264d..c12d197 100644
--- a/http/server.go
+++ b/http/server.go
@@ -1,4 +1,8 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
+
+// TINYGO: atomic.Pointer and atomic.Uint64 are added in Go 1.19, so keep
+// pre-1.19 code to cover min TinyGo.  If TinyGo min moves to 1.19 or higher,
+// then these can be converted to atomic.Pointer and atomic.Uint64.
 
 // TINYGO: Removed ALPN protocol support
 // TINYGO: Removed some HTTP/2 support
@@ -400,11 +404,11 @@ func (cw *chunkWriter) Write(p []byte) (n int, err error) {
 	return
 }
 
-func (cw *chunkWriter) flush() {
+func (cw *chunkWriter) flush() error {
 	if !cw.wroteHeader {
 		cw.writeHeader(nil)
 	}
-	cw.res.conn.bufw.Flush()
+	return cw.res.conn.bufw.Flush()
 }
 
 func (cw *chunkWriter) close() {
@@ -435,9 +439,9 @@ type response struct {
 	wants10KeepAlive bool               // HTTP/1.0 w/ Connection "keep-alive"
 	wantsClose       bool               // HTTP request has Connection "close"
 
-	// canWriteContinue is a boolean value accessed as an atomic int32
-	// that says whether or not a 100 Continue header can be written
-	// to the connection.
+	// canWriteContinue is an atomic boolean that says whether or
+	// not a 100 Continue header can be written to the
+	// connection.
 	// writeContinueMu must be held while writing the header.
 	// These two fields together synchronize the body reader (the
 	// expectContinueReader, which wants to write 100 Continue)
@@ -494,6 +498,14 @@ type response struct {
 	didCloseNotify int32 // atomic (only 0->1 winner should send)
 }
 
+func (c *response) SetReadDeadline(deadline time.Time) error {
+	return c.conn.rwc.SetReadDeadline(deadline)
+}
+
+func (c *response) SetWriteDeadline(deadline time.Time) error {
+	return c.conn.rwc.SetWriteDeadline(deadline)
+}
+
 // TrailerPrefix is a magic prefix for ResponseWriter.Header map keys
 // that, if present, signals that the map entry is actually for
 // the response trailers, and not the response headers. The prefix
@@ -514,11 +526,11 @@ const TrailerPrefix = "Trailer:"
 func (w *response) finalTrailers() Header {
 	var t Header
 	for k, vv := range w.handlerHeader {
-		if strings.HasPrefix(k, TrailerPrefix) {
+		if kk, found := strings.CutPrefix(k, TrailerPrefix); found {
 			if t == nil {
 				t = make(Header)
 			}
-			t[strings.TrimPrefix(k, TrailerPrefix)] = vv
+			t[kk] = vv
 		}
 	}
 	for _, k := range w.trailers {
@@ -560,12 +572,6 @@ func (w *response) requestTooLarge() {
 	}
 }
 
-// needsSniff reports whether a Content-Type still needs to be sniffed.
-func (w *response) needsSniff() bool {
-	_, haveType := w.handlerHeader["Content-Type"]
-	return !w.cw.wroteHeader && !haveType && w.written < sniffLen
-}
-
 // writerOnly hides an io.Writer value's optional ReadFrom method
 // from io.Copy.
 type writerOnly struct {
@@ -754,8 +760,8 @@ func (cr *connReader) handleReadError(_ error) {
 
 // may be called from multiple goroutines.
 func (cr *connReader) closeNotify() {
-	res, _ := cr.conn.curReq.Load().(*response)
-	if res != nil && atomic.CompareAndSwapInt32(&res.didCloseNotify, 0, 1) {
+	res := cr.conn.curReq.Load()
+	if res != nil && !res.didCloseNotify.Swap(true) {
 		res.closeNotifyCh <- true
 	}
 }
@@ -1706,11 +1712,19 @@ func (w *response) closedRequestBodyEarly() bool {
 }
 
 func (w *response) Flush() {
+	w.FlushError()
+}
+
+func (w *response) FlushError() error {
 	if !w.wroteHeader {
 		w.WriteHeader(StatusOK)
 	}
-	w.w.Flush()
-	w.cw.flush()
+	err := w.w.Flush()
+	e2 := w.cw.flush()
+	if err == nil {
+		err = e2
+	}
+	return err
 }
 
 func (c *conn) finalFlush() {
@@ -1964,6 +1978,7 @@ func (c *conn) serve(ctx context.Context) {
 			return
 		}
 		w.finishRequest()
+		c.rwc.SetWriteDeadline(time.Time{})
 		if !w.shouldReuseConnection() {
 			if w.requestBodyLimitHit || w.closedRequestBodyEarly() {
 				c.closeWriteAndWait()
@@ -1983,10 +1998,18 @@ func (c *conn) serve(ctx context.Context) {
 
 		if d := c.server.idleTimeout(); d != 0 {
 			c.rwc.SetReadDeadline(time.Now().Add(d))
-			if _, err := c.bufr.Peek(4); err != nil {
-				return
-			}
+		} else {
+			c.rwc.SetReadDeadline(time.Time{})
 		}
+
+		// Wait for the connection to become readable again before trying to
+		// read the next request. This prevents a ReadHeaderTimeout or
+		// ReadTimeout from starting until the first bytes of the next request
+		// have been received.
+		if _, err := c.bufr.Peek(4); err != nil {
+			return
+		}
+
 		c.rwc.SetReadDeadline(time.Time{})
 	}
 }
@@ -2548,6 +2571,10 @@ type Server struct {
 
 	Handler Handler // handler to invoke, http.DefaultServeMux if nil
 
+	// DisableGeneralOptionsHandler, if true, passes "OPTIONS *" requests to the Handler,
+	// otherwise responds with 200 OK and Content-Length: 0.
+	DisableGeneralOptionsHandler bool
+
 	// TLSConfig optionally provides a TLS configuration for use
 	// by ServeTLS and ListenAndServeTLS. Note that this value is
 	// cloned by ServeTLS and ListenAndServeTLS, so it's not
@@ -2629,37 +2656,11 @@ type Server struct {
 	mu         sync.Mutex
 	listeners  map[*net.Listener]struct{}
 	activeConn map[*conn]struct{}
-	doneChan   chan struct{}
 	onShutdown []func()
 
 	listenerGroup sync.WaitGroup
 }
 
-func (s *Server) getDoneChan() <-chan struct{} {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	return s.getDoneChanLocked()
-}
-
-func (s *Server) getDoneChanLocked() chan struct{} {
-	if s.doneChan == nil {
-		s.doneChan = make(chan struct{})
-	}
-	return s.doneChan
-}
-
-func (s *Server) closeDoneChanLocked() {
-	ch := s.getDoneChanLocked()
-	select {
-	case <-ch:
-		// Already closed. Don't close again.
-	default:
-		// Safe to close here. We're the only closer, guarded
-		// by s.mu.
-		close(ch)
-	}
-}
-
 // Close immediately closes all active net.Listeners and any
 // connections in state StateNew, StateActive, or StateIdle. For a
 // graceful shutdown, use Shutdown.
@@ -2725,7 +2726,6 @@ func (srv *Server) Shutdown(ctx context.Context) error {
 
 	srv.mu.Lock()
 	lnerr := srv.closeListenersLocked()
-	srv.closeDoneChanLocked()
 	for _, f := range srv.onShutdown {
 		go f()
 	}
@@ -2869,7 +2869,7 @@ func (sh serverHandler) ServeHTTP(rw ResponseWriter, req *Request) {
 	if handler == nil {
 		handler = DefaultServeMux
 	}
-	if req.RequestURI == "*" && req.Method == "OPTIONS" {
+	if !sh.srv.DisableGeneralOptionsHandler && req.RequestURI == "*" && req.Method == "OPTIONS" {
 		handler = globalOptionsHandler{}
 	}
 
@@ -2984,10 +2984,8 @@ func (srv *Server) Serve(l net.Listener) error {
 	for {
 		rw, err := l.Accept()
 		if err != nil {
-			select {
-			case <-srv.getDoneChan():
+			if srv.shuttingDown() {
 				return ErrServerClosed
-			default:
 			}
 			if ne, ok := err.(net.Error); ok && ne.Temporary() {
 				if tempDelay == 0 {
diff --git a/http/sniff.go b/http/sniff.go
index 3fee912..66c55b3 100644
--- a/http/sniff.go
+++ b/http/sniff.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/status.go b/http/status.go
index cd3db73..ec4f1ee 100644
--- a/http/status.go
+++ b/http/status.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/http/transfer.go b/http/transfer.go
index 38bd70f..e528968 100644
--- a/http/transfer.go
+++ b/http/transfer.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // TINYGO: Removed trace stuff
 // TINYGO: Hook readTransfer is onEOF callback to get notified when request of
@@ -553,7 +553,7 @@ func readTransfer(msg any, r *bufio.Reader, onEOF func()) (err error) {
 	// or close connection when finished, since multipart is not supported yet
 	switch {
 	case t.Chunked:
-		if noResponseBodyExpected(t.RequestMethod) || !bodyAllowedForStatus(t.StatusCode) {
+		if isResponse && (noResponseBodyExpected(t.RequestMethod) || !bodyAllowedForStatus(t.StatusCode)) {
 			t.Body = NoBody
 		} else {
 			t.Body = &body{src: internal.NewChunkedReader(r), hdr: msg, r: r, closing: t.Close, onHitEOF: onEOF}
@@ -596,7 +596,7 @@ func readTransfer(msg any, r *bufio.Reader, onEOF func()) (err error) {
 	return nil
 }
 
-// Checks whether chunked is part of the encodings stack
+// Checks whether chunked is part of the encodings stack.
 func chunked(te []string) bool { return len(te) > 0 && te[0] == "chunked" }
 
 // Checks whether the encoding is explicitly "identity".
@@ -687,14 +687,7 @@ func fixLength(isResponse bool, status int, requestMethod string, header Header,
 	}
 
 	// Logic based on response type or status
-	if noResponseBodyExpected(requestMethod) {
-		// For HTTP requests, as part of hardening against request
-		// smuggling (RFC 7230), don't allow a Content-Length header for
-		// methods which don't permit bodies. As an exception, allow
-		// exactly one Content-Length header if its value is "0".
-		if isRequest && len(contentLens) > 0 && !(len(contentLens) == 1 && contentLens[0] == "0") {
-			return 0, fmt.Errorf("http: method cannot contain a Content-Length; got %q", contentLens)
-		}
+	if isResponse && noResponseBodyExpected(requestMethod) {
 		return 0, nil
 	}
 	if status/100 == 1 {
diff --git a/http/transport.go b/http/transport.go
index a5f0f49..ae29865 100644
--- a/http/transport.go
+++ b/http/transport.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/ip.go b/ip.go
index 1a3a0b6..16477a6 100644
--- a/ip.go
+++ b/ip.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/iprawsock.go b/iprawsock.go
index 8f82ec8..f39850e 100644
--- a/iprawsock.go
+++ b/iprawsock.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/ipsock.go b/ipsock.go
index 52d1f7d..3ab9ebf 100644
--- a/ipsock.go
+++ b/ipsock.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/mac.go b/mac.go
index 320b209..2c855cb 100644
--- a/mac.go
+++ b/mac.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/mac_test.go b/mac_test.go
index cad884f..8bd8ba8 100644
--- a/mac_test.go
+++ b/mac_test.go
@@ -1,3 +1,5 @@
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
+
 // Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
diff --git a/net.go b/net.go
index bd6cff4..e66e19b 100644
--- a/net.go
+++ b/net.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/parse.go b/parse.go
index b263271..1a5e6c1 100644
--- a/parse.go
+++ b/parse.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied from Go 1.19.3 official implementation.
+// TINYGO: The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -238,7 +238,7 @@ func lowerASCII(b byte) byte {
 }
 
 // trimSpace returns x without any leading or trailing ASCII whitespace.
-func trimSpace(x []byte) []byte {
+func trimSpace(x string) string {
 	for len(x) > 0 && isSpace(x[0]) {
 		x = x[1:]
 	}
@@ -255,37 +255,19 @@ func isSpace(b byte) bool {
 
 // removeComment returns line, removing any '#' byte and any following
 // bytes.
-func removeComment(line []byte) []byte {
-	if i := bytealg.IndexByte(line, '#'); i != -1 {
+func removeComment(line string) string {
+	if i := bytealg.IndexByteString(line, '#'); i != -1 {
 		return line[:i]
 	}
 	return line
 }
 
-// foreachLine runs fn on each line of x.
-// Each line (except for possibly the last) ends in '\n'.
-// It returns the first non-nil error returned by fn.
-func foreachLine(x []byte, fn func(line []byte) error) error {
-	for len(x) > 0 {
-		nl := bytealg.IndexByte(x, '\n')
-		if nl == -1 {
-			return fn(x)
-		}
-		line := x[:nl+1]
-		x = x[nl+1:]
-		if err := fn(line); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 // foreachField runs fn on each non-empty run of non-space bytes in x.
 // It returns the first non-nil error returned by fn.
-func foreachField(x []byte, fn func(field []byte) error) error {
+func foreachField(x string, fn func(field string) error) error {
 	x = trimSpace(x)
 	for len(x) > 0 {
-		sp := bytealg.IndexByte(x, ' ')
+		sp := bytealg.IndexByteString(x, ' ')
 		if sp == -1 {
 			return fn(x)
 		}
diff --git a/pipe.go b/pipe.go
index 238da0c..b61a4dc 100644
--- a/pipe.go
+++ b/pipe.go
@@ -1,4 +1,4 @@
-// The following is copied from Go 1.19.3 official implementation.
+// The following is copied from Go 1.20.5 official implementation.
 
 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/tcpsock.go b/tcpsock.go
index 42af855..90605b7 100644
--- a/tcpsock.go
+++ b/tcpsock.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/tlssock.go b/tlssock.go
index f4f228b..639e998 100644
--- a/tlssock.go
+++ b/tlssock.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2010 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/udpsock.go b/udpsock.go
index f782c5f..086668b 100644
--- a/udpsock.go
+++ b/udpsock.go
@@ -1,4 +1,4 @@
-// TINYGO: The following is copied and modified from Go 1.19.3 official implementation.
+// TINYGO: The following is copied and modified from Go 1.20.5 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style