tabs, newlines and crs are valid XML characters.
(backport from rev. 56551)
diff --git a/Doc/lib/libxmlrpclib.tex b/Doc/lib/libxmlrpclib.tex
index f2975d6..ab9ef97 100644
--- a/Doc/lib/libxmlrpclib.tex
+++ b/Doc/lib/libxmlrpclib.tex
@@ -91,7 +91,8 @@
\samp{>}, and \samp{\&} will be automatically escaped. However, it's
the caller's responsibility to ensure that the string is free of
characters that aren't allowed in XML, such as the control characters
-with ASCII values between 0 and 31; failing to do this will result in
+with ASCII values between 0 and 31 (except, of course, tab, newline and
+carriage return); failing to do this will result in
an XML-RPC request that isn't well-formed XML. If you have to pass
arbitrary strings via XML-RPC, use the \class{Binary} wrapper class
described below.