Index: openacs-4/packages/xotcl-core/tcl/chat-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-core/tcl/Attic/chat-procs.tcl,v
diff -u -N -r1.36 -r1.37
--- openacs-4/packages/xotcl-core/tcl/chat-procs.tcl	28 Sep 2018 11:44:23 -0000	1.36
+++ openacs-4/packages/xotcl-core/tcl/chat-procs.tcl	4 Oct 2018 16:36:23 -0000	1.37
@@ -253,7 +253,7 @@
   Chat instproc noencode    {string} {set string}
   Chat instproc encode      {string} {my [:encoder] $string}
   Chat instproc json_encode {string} {
-    string map [list \n \\n \" \\\" ' {\\'}] $string
+    string map [list \n \\n \" \\\" ' {\\'} \\ \\\\] $string
   }
 
   Chat instproc json_encode_msg {msg} {