.oindex "&%-MCG%&"
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that an
-alternate queue is used, named by the following option.
+alternate queue is used, named by the following argument.
+
+.vitem &%-MCK%&
+.oindex "&%-MCK%&"
+This option is not intended for use by external callers. It is used internally
+by Exim in conjunction with the &%-MC%& option. It signifies that an
+remote host supports the ESMTP &_CHUNKING_& extension.
.vitem &%-MCP%&
.oindex "&%-MCP%&"
.option tls_eccurve main string&!! &`auto`&
.cindex TLS "EC cryptography"
-This option selects a EC curve for use by Exim.
+This option selects a EC curve for use by Exim when used with OpenSSL.
+It has no effect when Exim is used with GnuTLS.
After expansion it must contain a valid EC curve parameter, such as
&`prime256v1`&, &`secp384r1`&, or &`P-512`&. Consult your OpenSSL manual
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