diff --git a/CHANGES b/CHANGES
index 0d25d9c..43c9cd8 100644
--- a/CHANGES
+++ b/CHANGES
@@ -20,6 +20,11 @@ Features:
 	Added option ipv6-join-source-group.
 	Thanks to Martin Buck and David Schweizer for sending patches.
 
+	Added option http-version to PROXY-CONNECT address to support servers
+	that are not able to handle HTTP version 1.0
+	Test: PROXY_HTTPVERSION
+	Feature inspired by Robin Palotai.
+
 Corrections:
 	When a sub process (EXEC, SYSTEM) terminated with exit code other than
 	0, its last sent data might have been lost depending on timing of read/
diff --git a/doc/socat.yo b/doc/socat.yo
index f7eb401..b2bd711 100644
--- a/doc/socat.yo
+++ b/doc/socat.yo
@@ -2421,6 +2421,10 @@ Options that can be provided with HTTP type addresses. The only HTTP address
 currently implemented is link(proxy-connect)(ADDRESS_PROXY_CONNECT).
 
 startdit()
+label(OPTION_HTTP_VERSION)dit(bf(tt(http-version=<string>)))
+   Changes the default "1.0" that is sent to the server in the initial HTTP
+   request. Currently it has not other effect, in particular it does not
+   provide any means to send a Host header.
 label(OPTION_PROXYPORT)dit(bf(tt(proxyport=<TCP service>)))
    Overrides the default HTTP proxy port 8080 with
    link(<TCP service>)(TYPE_TCP_SERVICE).
diff --git a/proxy.sh b/proxy.sh
index 6c24126..9f3c53e 100755
--- a/proxy.sh
+++ b/proxy.sh
@@ -7,8 +7,8 @@
 # accepts and answers correct HTTP CONNECT requests on stdio, and tries to
 # establish the connection to the given server.
 # it is required for socats test.sh
-# for TCP, use this script as:
-# socat tcp-l:8080,reuseaddr,fork exec:"proxy.sh",nofork
+# for TCP, use this script like:
+# socat TCP-L:8080,reuseaddr,fork EXEC:"proxy.sh",nofork
 
 # 20130622  GR allow hostnames, not only IP addresses
 
diff --git a/proxyecho.sh b/proxyecho.sh
index db7efd5..f5d0706 100755
--- a/proxyecho.sh
+++ b/proxyecho.sh
@@ -7,7 +7,9 @@
 # accepts and answers correct HTTP CONNECT requests, but then just echoes data.
 # it is required for test.sh
 # for TCP, use this script as:
-# socat tcp-l:8080,reuseaddr,crlf system:"proxyecho.sh"
+# socat TCP-L:8080,reuseaddr,crlf SYSTEM:"proxyecho.sh"
+
+# 20230423  GR Added option -V to require particular HTTP version
 
 if type socat >/dev/null 2>&1; then
     SOCAT=socat
@@ -24,11 +26,12 @@ HP-UX|OSF1)
     ;;
 esac
 
-SPACES=" "
+SPACES=" " REQVER=1.0
 while [ -n "$1" ]; do
     case "$1" in
     -w) n="$2"; while [ "$n" -gt 0 ]; do SPACES="$SPACES "; n=$((n-1)); done
 	shift ;;
+    -V) shift; REQVER="$1" ;;
     #-s) STAT="$2"; shift ;;
     esac
     shift
@@ -36,14 +39,18 @@ done
 
 # read and parse HTTP request
 read l
-if echo "$l" |egrep '^CONNECT +[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+:[0-9]+ +HTTP/1.[01]$' >/dev/null
+if ! echo "$l" |egrep '^CONNECT +[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+:[0-9]+ +HTTP/[1-3].[0-9]$' >/dev/null
 then
-    : go on below
-else
     echo "HTTP/1.0${SPACES}500 Bad Request"
     echo
     exit
 fi
+if ! echo "$l" |egrep '^CONNECT +[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+:[0-9]+ +HTTP/'"$REQVER"'$' >/dev/null
+then
+    echo "HTTP/1.0${SPACES}426 Upgrade Required"
+    echo
+    exit
+fi
 
 # read more headers until empty line
 while [ -n "$l" ]; do
@@ -51,7 +58,7 @@ while [ -n "$l" ]; do
 done
 
 # send status
-echo "HTTP/1.0${SPACES}200 OK"
+echo "HTTP/$REQVER${SPACES}200 OK"
 # send empty line
 echo
 
diff --git a/test.sh b/test.sh
index 676b8dd..a07ffff 100755
--- a/test.sh
+++ b/test.sh
@@ -4128,27 +4128,31 @@ te="$td/test$N.stderr"
 tdiff="$td/test$N.diff"
 da="test$N $(date) $RANDOM"; da="$da$($ECHO '\r')"
 newport tcp4 	# provide free port number in $PORT
-#CMD2="$TRACE $SOCAT $opts tcp-l:$PORT,crlf SYSTEM:\"read; read; $ECHO \\\"HTTP/1.0 200 OK\n\\\"; cat\""
-CMD2="$TRACE $SOCAT $opts tcp4-l:$PORT,reuseaddr,crlf exec:\"/usr/bin/env bash proxyecho.sh -w 2\""
-CMD="$TRACE $SOCAT $opts - proxy:$LOCALHOST:127.0.0.1:1000,pf=ip4,proxyport=$PORT"
+#CMD2="$TRACE $SOCAT $opts TCP-L:$PORT,crlf SYSTEM:\"read; read; $ECHO \\\"HTTP/1.0 200 OK\n\\\"; cat\""
+CMD0="$TRACE $SOCAT $opts TCP4-L:$PORT,reuseaddr,crlf EXEC:\"/usr/bin/env bash proxyecho.sh -w 2\""
+CMD1="$TRACE $SOCAT $opts - PROXY:$LOCALHOST:127.0.0.1:1000,pf=ip4,proxyport=$PORT"
 printf "test $F_n $TEST... " $N
-eval "$CMD2 2>\"${te}1\" &"
+eval "$CMD0 2>\"${te}1\" &"
 pid=$!	# background process id
 waittcp4port $PORT 1
-echo "$da" |$CMD >"$tf" 2>"${te}2"
+echo "$da" |$CMD1 >"$tf" 2>"${te}0"
 if ! echo "$da" |diff - "$tf" >"$tdiff"; then
     $PRINTF "$FAILED: $TRACE $SOCAT:\n"
-    echo "$CMD2 &"
-    echo "$CMD"
-    cat "${te}1"
-    cat "${te}2"
+    echo "$CMD0 &"
+    cat "${te}0" >&2
+    echo "$CMD1"
+    cat "${te}1" >&2
+    echo "diff:"
     cat "$tdiff"
     numFAIL=$((numFAIL+1))
     listFAIL="$listFAIL $N"
 else
-   $PRINTF "$OK\n"
-   if [ -n "$debug" ]; then cat "${te}1" "${te}2"; fi
-   numOK=$((numOK+1))
+    $PRINTF "$OK\n"
+    if [ "$VERBOSE" ]; then echo "$CMD0 &"; fi
+    if [ "$debug" ];   then cat "${te}0" >&2; fi
+    if [ "$VERBOSE" ]; then echo "$CMD1"; fi
+    if [ "$debug" ];   then cat "${te}1" >&2; fi
+    numOK=$((numOK+1))
 fi
 kill $pid 2>/dev/null
 wait
@@ -15153,6 +15157,71 @@ fi # NUMCOND
 esac
 N=$((N+1))
 
+
+# Test the http-version of the PROXY-CONNECT address
+NAME=PROXY_HTTPVERSION
+case "$TESTS" in
+*%$N%*|*%functions%*|*%proxy%*|*%$NAME%*)
+TEST="$NAME: PROXY-CONNECT with option http-version"
+if ! eval $NUMCOND; then :;
+elif ! $(type proxyecho.sh >/dev/null 2>&1); then
+    $PRINTF "test $F_n $TEST... ${YELLOW}proxyecho.sh not available${NORMAL}\n" $N
+    numCANT=$((numCANT+1))
+    listCANT="$listCANT $N"
+elif ! F=$(testfeats IP4 TCP LISTEN EXEC STDIO PROXY); then
+    $PRINTF "test $F_n $TEST... ${YELLOW}Feature $F not available${NORMAL}\n" $N
+    numCANT=$((numCANT+1))
+    listCANT="$listCANT $N"
+elif ! A=$(testaddrs TCP4-LISTEN EXEC STDIO PROXY-CONNECT); then
+    $PRINTF "test $F_n $TEST... ${YELLOW}Address $A not available in $SOCAT${NORMAL}\n" $N
+    numCANT=$((numCANT+1))
+    listCANT="$listCANT $N"
+elif ! o=$(testoptions so-reuseaddr crlf pf proxyport http-version) >/dev/null; then
+    $PRINTF "test $F_n $TEST... ${YELLOW}Option $o not available in $SOCAT${NORMAL}\n" $N
+    numCANT=$((numCANT+1))
+    listCANT="$listCANT $N"
+elif ! runsip4 >/dev/null; then
+    $PRINTF "test $F_n $TEST... ${YELLOW}IPv4 not available${NORMAL}\n" $N
+    numCANT=$((numCANT+1))
+    listCANT="$listCANT $N"
+else
+ts="$td/test$N.sh"
+tf="$td/test$N.stdout"
+te="$td/test$N.stderr"
+tdiff="$td/test$N.diff"
+da="test$N $(date) $RANDOM"; da="$da$($ECHO '\r')"
+CMD0="$TRACE $SOCAT $opts TCP4-L:$PORT,reuseaddr,crlf EXEC:\"/usr/bin/env bash proxyecho.sh -V 1.1\""
+CMD1="$TRACE $SOCAT $opts - PROXY:$LOCALHOST:127.0.0.1:1000,pf=ip4,proxyport=$PORT,http-version=1.1"
+printf "test $F_n $TEST... " $N
+eval "$CMD0 2>\"${te}1\" &"
+pid=$!	# background process id
+waittcp4port $PORT 1
+echo "$da" |$CMD1 >"$tf" 2>"${te}0"
+if ! echo "$da" |diff - "$tf" >"$tdiff"; then
+    $PRINTF "$FAILED: $TRACE $SOCAT:\n"
+    echo "$CMD0 &" >&2
+    cat "${te}0"
+    echo "$CMD1" >&2
+    cat "${te}1"
+    echo "diff:"
+    cat "$tdiff"
+    numFAIL=$((numFAIL+1))
+    listFAIL="$listFAIL $N"
+else
+    $PRINTF "$OK\n"
+    if [ "$VERBOSE" ]; then echo "$CMD0 &"; fi
+    if [ "$debug" ];   then cat "${te}0" >&2; fi
+    if [ "$VERBOSE" ]; then echo "$CMD1"; fi
+    if [ "$debug" ];   then cat "${te}1" >&2; fi
+    numOK=$((numOK+1))
+fi
+kill $pid 2>/dev/null
+wait
+fi ;; # NUMCOND, feats
+esac
+PORT=$((PORT+1))
+
+
 # end of common tests
 
 ##################################################################################
diff --git a/xio-proxy.c b/xio-proxy.c
index 47d133f..941f1fe 100644
--- a/xio-proxy.c
+++ b/xio-proxy.c
@@ -27,6 +27,7 @@ static int xioopen_proxy_connect(int argc, const char *argv[], struct opt *opts,
 
 const struct optdesc opt_proxyport = { "proxyport", NULL, OPT_PROXYPORT, GROUP_HTTP, PH_LATE, TYPE_STRING, OFUNC_SPEC };
 const struct optdesc opt_ignorecr  = { "ignorecr",  NULL, OPT_IGNORECR,  GROUP_HTTP, PH_LATE, TYPE_BOOL,  OFUNC_SPEC };
+const struct optdesc opt_http_version              = { "http-version",              NULL,            OPT_HTTP_VERSION,              GROUP_HTTP, PH_LATE, TYPE_STRING,  OFUNC_SPEC };
 const struct optdesc opt_proxy_resolve   = { "proxy-resolve",   "resolve", OPT_PROXY_RESOLVE,   GROUP_HTTP, PH_LATE, TYPE_BOOL,  OFUNC_SPEC };
 const struct optdesc opt_proxy_authorization  = { "proxy-authorization",  "proxyauth", OPT_PROXY_AUTHORIZATION,  GROUP_HTTP, PH_LATE, TYPE_STRING,  OFUNC_SPEC };
 const struct optdesc opt_proxy_authorization_file  = { "proxy-authorization-file",  "proxyauthfile", OPT_PROXY_AUTHORIZATION_FILE,  GROUP_HTTP, PH_LATE, TYPE_STRING,  OFUNC_SPEC };
@@ -239,6 +240,7 @@ int _xioopen_proxy_prepare(struct proxyvars *proxyvars, struct opt *opts,
 
    retropt_bool(opts, OPT_IGNORECR, &proxyvars->ignorecr);
    retropt_bool(opts, OPT_PROXY_RESOLVE, &proxyvars->doresolve);
+   retropt_string(opts, OPT_HTTP_VERSION,             &proxyvars->version);
    retropt_string(opts, OPT_PROXY_AUTHORIZATION, &proxyvars->authstring);
    retropt_string(opts, OPT_PROXY_AUTHORIZATION_FILE, &proxyvars->authfile);
 
@@ -331,8 +333,11 @@ int _xioopen_proxy_connect(struct single *xfd,
    ssize_t sresult;
 
    /* generate proxy request header - points to final target */
-   rv = snprintf(request, CONNLEN, "CONNECT %s:%u HTTP/1.0\r\n",
-		 proxyvars->targetaddr, proxyvars->targetport);
+   if (proxyvars->version == NULL) {
+      proxyvars->version = "1.0";
+   }
+   rv = snprintf(request, CONNLEN, "CONNECT %s:%u HTTP/%s\r\n",
+		 proxyvars->targetaddr, proxyvars->targetport, proxyvars->version);
    if (rv >= CONNLEN || rv < 0) {
       Error("_xioopen_proxy_connect(): PROXY CONNECT buffer too small");
       return -1;
diff --git a/xio-proxy.h b/xio-proxy.h
index f74a9bc..ff8530b 100644
--- a/xio-proxy.h
+++ b/xio-proxy.h
@@ -8,6 +8,7 @@
 
 struct proxyvars {
    bool ignorecr;
+   char *version;
    bool doresolve;
    char *authstring;
    char *authfile;
@@ -17,6 +18,7 @@ struct proxyvars {
 
 extern const struct optdesc opt_proxyport;
 extern const struct optdesc opt_ignorecr;
+extern const struct optdesc opt_http_version;
 extern const struct optdesc opt_proxy_resolve;
 extern const struct optdesc opt_proxy_authorization;
 extern const struct optdesc opt_proxy_authorization_file;
diff --git a/xioopts.c b/xioopts.c
index d93dcaf..750caa5 100644
--- a/xioopts.c
+++ b/xioopts.c
@@ -613,6 +613,7 @@ const struct optname optionnames[] = {
 #if WITH_LIBWRAP && defined(HAVE_HOSTS_DENY_TABLE)
 	IF_IPAPP  ("hosts-deny",	&opt_tcpwrap_hosts_deny_table)
 #endif
+	IF_PROXY  ("http-version",	&opt_http_version)
 	IF_TERMIOS("hup",	&opt_hupcl)
 	IF_TERMIOS("hupcl",	&opt_hupcl)
 #ifdef I_POP
diff --git a/xioopts.h b/xioopts.h
index 084cb7b..32c3ab3 100644
--- a/xioopts.h
+++ b/xioopts.h
@@ -337,6 +337,7 @@ enum e_optcode {
    OPT_GROUP_EARLY,
    OPT_GROUP_LATE,
    OPT_HISTORY_FILE,	/* readline history file */
+   OPT_HTTP_VERSION,
    OPT_HUPCL,		/* termios.c_cflag */
    OPT_ICANON,		/* termios.c_lflag */
    OPT_ICRNL,		/* termios.c_iflag */