Index: subversion/include/svn_config.h
===================================================================
--- subversion/include/svn_config.h	(revision 1495417)
+++ subversion/include/svn_config.h	(working copy)
@@ -95,6 +95,8 @@
 #define SVN_CONFIG_OPTION_HTTP_BULK_UPDATES         "http-bulk-updates"
 /** @since New in 1.8. */
 #define SVN_CONFIG_OPTION_HTTP_MAX_CONNECTIONS      "http-max-connections"
+/** @since New in 1.9. */
+#define SVN_CONFIG_OPTION_HTTP_FORCE_HTTP10      "http-force-http10"
 
 #define SVN_CONFIG_CATEGORY_CONFIG          "config"
 #define SVN_CONFIG_SECTION_AUTH                 "auth"
Index: subversion/libsvn_ra_serf/ra_serf.h
===================================================================
--- subversion/libsvn_ra_serf/ra_serf.h	(revision 1495455)
+++ subversion/libsvn_ra_serf/ra_serf.h	(working copy)
@@ -144,6 +144,9 @@
      HTTP/1.0. Thus, we cannot send chunked requests.  */
   svn_boolean_t http10;
 
+  /* Force using HTTP/1.0 even server declares HTTP/1.1 support. */
+  svn_boolean_t force_http10;
+
   /* Our Version-Controlled-Configuration; may be NULL until we know it. */
   const char *vcc_url;
 
Index: subversion/libsvn_ra_serf/serf.c
===================================================================
--- subversion/libsvn_ra_serf/serf.c	(revision 1495455)
+++ subversion/libsvn_ra_serf/serf.c	(working copy)
@@ -225,6 +225,10 @@
                                SVN_CONFIG_OPTION_HTTP_MAX_CONNECTIONS,
                                SVN_CONFIG_DEFAULT_OPTION_HTTP_MAX_CONNECTIONS));
 
+  SVN_ERR(svn_config_get_bool(config, &session->force_http10,
+                              SVN_CONFIG_SECTION_GLOBAL,
+                              SVN_CONFIG_OPTION_HTTP_FORCE_HTTP10, FALSE));
+
   if (config)
     server_group = svn_config_find_group(config,
                                          session->session_url.hostname,
@@ -281,6 +285,11 @@
                                    server_group,
                                    SVN_CONFIG_OPTION_HTTP_MAX_CONNECTIONS,
                                    session->max_connections));
+
+      SVN_ERR(svn_config_get_bool(config, &session->force_http10,
+                                  server_group,
+                                  SVN_CONFIG_OPTION_HTTP_FORCE_HTTP10,
+                                  session->force_http10));
     }
 
   /* Don't allow the http-max-connections value to be larger than our
Index: subversion/libsvn_ra_serf/util.c
===================================================================
--- subversion/libsvn_ra_serf/util.c	(revision 1495455)
+++ subversion/libsvn_ra_serf/util.c	(working copy)
@@ -1863,7 +1863,7 @@
       handler->sline.reason = apr_pstrdup(handler->handler_pool, sl.reason);
 
       /* HTTP/1.1? (or later)  */
-      if (sl.version != SERF_HTTP_10)
+      if (sl.version != SERF_HTTP_10 && !handler->session->force_http10)
         handler->session->http10 = FALSE;
     }
 
Index: subversion/libsvn_subr/config_file.c
===================================================================
--- subversion/libsvn_subr/config_file.c	(revision 1495417)
+++ subversion/libsvn_subr/config_file.c	(working copy)
@@ -810,6 +810,8 @@
         "###   http-max-connections       Maximum number of parallel server" NL
         "###                              connections to use for any given"  NL
         "###                              HTTP operation."                   NL
+        "###   http-force-http10          Force using HTTP/1.0 even server"  NL
+        "###                              declares HTTP/1.1 support."        NL
         "###   neon-debug-mask            Debug mask for Neon HTTP library"  NL
         "###   ssl-authority-files        List of files, each of a trusted CA"
                                                                              NL