Spec docs for IDNA2008 support

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 2be1373b080bad1323628cb82ca012a6c0f06bf2..919b36a146d5260aa27baa6594e6dd31da39f13c 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -38680,6 +38680,12 @@ Exim has support for Internationalised mail names.
 To include this it must be built with SUPPORT_I18N and the libidn library.
 Standards supported are RFCs 2060, 5890, 6530 and 6533.
 
+.new
+If Exim is built with SUPPORT_I18N_2008 (in addition to SUPPORT_I18N, not
+instead of it) then IDNA2008 is supported; this adds an extra library
+requirement, upon libidn2.
+.wen
+
 .section "MTA operations" SECTi18nMTA
 .cindex SMTPUTF8 "ESMTP option"
 The main configuration option &%smtputf8_advertise_hosts%& specifies