I18N: Move EAI support from Experimental to mainlineexim-4_87_RC1

32 files changed, 285 insertions, 201 deletions

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 418cb1a11..aabf85865 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -9373,6 +9373,19 @@ you can use
 condition = ${if >{$acl_m4}{3}}
 .endd
 
+
+
+.new
+.vitem &*${imapfolder{*&<&'foldername'&>&*}}*&
+.cindex expansion "imap folder"
+.cindex "&%imapfolder%& expansion item"
+This item converts a (possibly multilevel, or with non-ASCII characters)
+folder specification to a Maildir name for filesystem use.
+For information on internationalisation support see &<<SECTi18nMDA>>&.
+.wen
+
+
+
 .vitem &*${length{*&<&'string1'&>&*}{*&<&'string2'&>&*}}*&
 .cindex "expansion" "string truncation"
 .cindex "&%length%& expansion item"
@@ -10464,6 +10477,23 @@ This forces the letters in the string into upper-case.
 .cindex "expansion" "utf-8 forcing"
 .cindex "&%utf8clean%& expansion item"
 This replaces any invalid utf-8 sequence in the string by the character &`?`&.
+
+.new
+.vitem "&*${utf8_domain_to_alabel:*&<&'string'&>&*}*&" &&&
+       "&*${utf8_domain_from_alabel:*&<&'string'&>&*}*&" &&&
+       "&*${utf8_localpart_to_alabel:*&<&'string'&>&*}*&" &&&
+       "&*${utf8_localpart_from_alabel:*&<&'string'&>&*}*&"
+.cindex expansion UTF-8
+.cindex UTF-8 expansion
+.cindex EAI
+.cindex internationalisation
+.cindex "&%utf8_domain_to_alabel%& expansion item"
+.cindex "&%utf8_domain_from_alabel%& expansion item"
+.cindex "&%utf8_localpart_to_alabel%& expansion item"
+.cindex "&%utf8_localpart_from_alabel%& expansion item"
+These convert EAI mail name components between UTF-8 and a-label forms.
+For information on internationalisation support see &<<SECTi18nMTA>>&.
+.wen
 .endlist
 
 
@@ -13615,6 +13645,7 @@ See also the &'Policy controls'& section above.
 .row &%ignore_fromline_local%&       "allow &""From ""& from local SMTP"
 .row &%pipelining_advertise_hosts%&  "advertise pipelining to these hosts"
 .row &%prdr_enable%&                 "advertise PRDR to all hosts"
+.row &%smtputf8_advertise_hosts%&    "advertise SMTPUTF8 to these hosts"
 .row &%tls_advertise_hosts%&         "advertise TLS to these hosts"
 .endtable
 
@@ -16378,6 +16409,17 @@ example, instead of &"Administrative prohibition"&, it might give:
 550 failing address in "From" header is: <user@dom.ain
 .endd
 
+
+.new
+.option smtputf8_advertise_hosts main "host list&!!" *
+.cindex "SMTPUTF8" "advertising"
+When Exim is built with support for internationalised mail names,
+the availability therof is advertised in
+response to EHLO only to those client hosts that match this option. See
+chapter &<<CHAPi18n>>& for details of Exim's support for internationalisation.
+.wen
+
+
 .option spamd_address main string "see below"
 This option is available when Exim is compiled with the content-scanning
 extension. It specifies how Exim connects to SpamAssassin's &%spamd%& daemon.
@@ -28665,6 +28707,13 @@ data is read.
 
 &*Note:*& This control applies only to the current message, not to any others
 that are being submitted at the same time using &%-bs%& or &%-bS%&.
+
+.new
+.vitem &*control&~=&~utf8_downconvert*&
+This control enables conversion of UTF-8 in message addresses
+to a-label form.
+For details see &<<SECTi18nMTA>>&.
+.wen
 .endlist vlist
 
 
@@ -35215,6 +35264,7 @@ extensions (ESMTP), encryption, or authentication were used. If the SMTP
 session was encrypted, there is an additional X field that records the cipher
 suite that was used.
 
+.cindex log protocol
 The protocol is set to &"esmtpsa"& or &"esmtpa"& for messages received from
 hosts that have authenticated themselves using the SMTP AUTH command. The first
 value is used when the SMTP connection was encrypted (&"secure"&). In this case
@@ -35385,6 +35435,7 @@ the following table:
 &`id  `&        message id for incoming message
 &`P   `&        on &`<=`& lines: protocol used
 &`    `&        on &`=>`& and &`**`& lines: return path
+&`PRX `&        on &'<='& and&`=>`& lines: proxy address
 &`QT  `&        on &`=>`& lines: time spent on queue so far
 &`    `&        on &"Completed"& lines: time spent on queue
 &`R   `&        on &`<=`& lines: reference for local bounce
@@ -38144,13 +38195,13 @@ is an IP address and any subsequent elements are options.
 Options are a string <name>=<value>. 
 The list of options is in the following table:
 .display
-&`auth   `& authentication method
-&`name   `& authentication username
-&`pass   `& authentication password
-&`port   `& tcp port
-&`tmo    `& connection timeout
-&`pri    `& priority
-&`weight `& selection bias
+&'auth   '& authentication method
+&'name   '& authentication username
+&'pass   '& authentication password
+&'port   '& tcp port
+&'tmo    '& connection timeout
+&'pri    '& priority
+&'weight '& selection bias
 .endd
 
 More details on each of these options follows:
@@ -38198,6 +38249,127 @@ This will add a component tagged with &"PRX="& to the line.
 . ////////////////////////////////////////////////////////////////////////////
 . ////////////////////////////////////////////////////////////////////////////
 
+.chapter "Internationalisation" "CHAPi18n" &&&
+         "Internationalisation""
+.cindex internationalisation "email address"
+.cindex EAI
+.cindex i18n
+.cindex UTF-8 "mail name handling"
+
+.new
+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.
+
+.section "MTA operations" SECTi18nMTA
+.cindex SMTPUTF8 "ESMTP option"
+The main configuration option &%smtputf8_advertise_hosts%& specifies
+a host list.  If this matches the sending host and
+accept_8bitmime is true (the default) then the ESMTP option
+SMTPUTF8 will be advertised.
+
+If the sender specifies the SMTPUTF8 option on a MAIL command
+international handling for the message is enabled and
+the expansion variable &$message_smtputf8$& will have value TRUE.
+
+The option &%allow_utf8_domains%& is set to true for this
+message. All DNS lookups are converted to a-label form
+whatever the setting of &%allow_utf8_domains%&
+when Exim is built with SUPPORT_I18N.
+
+Both localparts and domain are maintained as the original
+UTF-8 form internally; any comparison or regular-expression use will
+require appropriate care.  Filenames created, eg. by
+the appendfile transport, will have UTF-8 names.
+
+Helo names sent by the smtp transport will have any UTF-8
+components expanded to a-label form,
+and any certificate name checks will be done using the a-label
+form of the name.
+
+.cindex log protocol
+.cindex SMTPUTF8 logging
+Log lines and Received-by: header lines will acquire a "utf8"
+prefix on the protocol element, eg. utf8esmtp.
+
+The following expansion operator can be used:
+.code
+${utf8_domain_to_alabel:str}
+${utf8_domain_from_alabel:str}
+${utf8_localpart_to_alabel:str}
+${utf8_localpart_from_alabel:str}
+.endd
+
+ACLs may use the following modifier:
+.display
+control = utf8_downconvert
+control = utf8_downconvert/<value>
+.endd
+This sets a flag requiring that addresses are converted to
+a-label form before smtp delivery, for use in a
+Message Submission Agent context.
+If a value is appended it may be:
+.display
+&`1  `& (default) mandatory downconversion
+&`0  `& no downconversion
+&`-1 `& if SMTPUTF8 not supported by destination host
+.endd
+
+If mua_wrapper is set, the utf8_downconvert control
+is initially set to -1.
+
+
+There is no explicit support for VRFY and EXPN.
+Configurations supporting these should inspect
+&$smtp_command_argument$& for an SMTPUTF8 argument.
+
+There is no support for LMTP on Unix sockets.
+Using the "lmtp" protocol option on an smtp transport,
+for LMTP over TCP, should work as expected.
+
+There is no support for DSN unitext handling,
+and no provision for converting logging from or to UTF-8.
+
+
+
+.section "MDA operations" SECTi18nMDA
+To aid in constructing names suitable for IMAP folders
+the following expansion operator can be used:
+.code
+${imapfolder {<string>} {<sep>} {<specials>}}
+.endd
+
+The string is converted from the charset specified by
+the "headers charset" command (in a filter file)
+or &%headers_charset%& main configuration option (otherwise),
+to the
+modified UTF-7 encoding specified by RFC 2060,
+with the following exception: All occurences of <sep>
+(which has to be a single character)
+are replaced with periods ("."), and all periods and slashes that are not
+<sep> and are not in the <specials> string are BASE64 encoded.
+
+The third argument can be omitted, defaulting to an empty string.
+The second argument can be omitted, defaulting to "/".
+
+This is the encoding used by Courier for Maildir names on disk, and followed
+by many other IMAP servers.
+
+Examples:
+.display
+&`${imapfolder {Foo/Bar}}       `& yields &`Foo.Bar`&
+&`${imapfolder {Foo/Bar}{.}{/}} `& yields &`Foo&&AC8-Bar`&
+&`${imapfolder {Räksmörgås}}    `& yields &`R&&AOQ-ksm&&APY-rg&&AOU-s`&
+.endd
+
+Note that the source charset setting is vital, and also that characters
+must be representable in UTF-16.
+
+.wen
+
+. ////////////////////////////////////////////////////////////////////////////
+. ////////////////////////////////////////////////////////////////////////////
+
 .chapter "Adding new drivers or lookup types" "CHID13" &&&
          "Adding drivers or lookups"
 .cindex "adding drivers"
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index c167f8392..eab4f6547 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -120,6 +120,9 @@ JH/26 Move PROXY support from Experimental to mainline, enabled for a build
       is renamed to hosts_proxy, and the proxy_{host,target}_{address,port}.
       variables are renamed to proxy_{local,external}_{address,port}.
 
+JH/27 Move Internationalisation support from Experimental to mainline, enabled
+      for a build by defining SUPPORT_I18N
+
 
 Exim version 4.86
 -----------------
diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index 45e7d1ba1..aa4cb464d 100644
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -1125,102 +1125,6 @@ $tls_out_tlsa_usage (detailed above).
 
 
 
-INTERNATIONAL
-------------------------------------------------------------
-SMTPUTF8
-Internationalised mail name handling.
-RFCs 6530, 6533, 5890
-
-Compile with EXPERIMENTAL_INTERNATIONAL and libidn.
-
-New main config option smtputf8_advertise_hosts, default '*',
-a host list.  If this matches the sending host and
-accept_8bitmime is true (the default) then the ESMTP option
-SMTPUTF8 will be advertised.
-
-If the sender specifies the SMTPUTF8 option on a MAIL command
-international handling for the message is enabled and
-the expansion variable $message_smtputf8 will have value TRUE.
-
-The option allow_utf8_domains is set to true for this
-message. All DNS lookups are converted to a-label form
-whatever the setting of allow_utf8_domains.
-
-Both localparts and domain are maintained as the original
-utf8 form internally; any matching or regex use will
-require appropriate care.  Filenames created, eg. by
-the appendfile transport, will have utf8 name.
-
-Helo names sent by the smtp transport will have any utf8
-components expanded to a-label form.
-
-Any certificate name checks will be done using the a-label
-form of the name.
-
-Log lines and Received-by: header lines will aquire a "utf8"
-prefix on the protocol element, eg. utf8esmtp.
-
-New expansion operators:
-	${utf8_domain_to_alabel:str}
-	${utf8_domain_from_alabel:str}
-	${utf8_localpart_to_alabel:str}
-	${utf8_localpart_from_alabel:str}
-
-New "control = utf8_downconvert" ACL modifier,
-sets a flag requiring that addresses are converted to
-a-label form before smtp delivery, for use in a
-Message Submission Agent context.  Can also be
-phrased as "control = utf8_downconvert/1" and is
-mandatory.  The flag defaults to zero and can be cleared
-by "control = utf8_downconvert/0".  The value "-1"
-may also be used, to use a-label for only if the
-destination host does not support SMTPUTF8.
-
-If mua_wrapper is set, the utf8_downconvert control
-defaults to -1 (convert if needed).
-
-
-There is no explicit support for VRFY and EXPN.
-Configurations supporting these should inspect
-$smtp_command_argument for an SMTPUTF8 argument.
-
-There is no support for LMTP on Unix sockets.
-Using the "lmtp" protocol option on an smtp transport,
-for LMTP over TCP, should work as expected.
-
-Known issues:
- - DSN unitext handling is not present
- - no provision for converting logging from or to UTF-8
-
-----
-IMAP folder names
-
-New expansion operator:
-
-${imapfolder {<string>} {<sep>} {<specials>}}
-
-The string is converted from the charset specified by the headers charset 
-command (in a filter file) or headers_charset global option, to the
-modified UTF-7 encoding specified by RFC 2060, with the following
-exception: All occurences of <sep> (which has to be a single character)
-are replaced with periods ("."), and all periods and slashes that aren't
-<sep> and are not in the <specials> string are BASE64 encoded.
-
-The third argument can be omitted, defaulting to an empty string.
-The second argument can be omitted, defaulting to "/".
-
-This is the encoding used by Courier for Maildir names on disk, and followed
-by many other IMAP servers.
-
-   Example 1: ${imapfolder {Foo/Bar}}       yields "Foo.Bar".
-   Example 2: ${imapfolder {Foo/Bar}{.}{/}} yields "Foo&AC8-Bar".
-   Example 3: ${imapfolder {Räksmörgås}}    yields "R&AOQ-ksm&APY-rg&AOU-s".
-
-Note that the source charset setting is vital, and also that characters
-must be representable in UTF-16.
-
-
-
 DSN extra information
 ---------------------
 If compiled with EXPERIMENTAL_DSN_INFO extra information will be added
diff --git a/src/src/EDITME b/src/src/EDITME
index a67343b3a..de25abd5e 100644
--- a/src/src/EDITME
+++ b/src/src/EDITME
@@ -496,11 +496,6 @@ EXIM_MONITOR=eximon.bin
 # Note: Enabling this unconditionally overrides DISABLE_DNSSEC
 # EXPERIMENTAL_DANE=yes
 
-# Uncomment the following to add Internationalisation features. You need to
-# have the IDN library installed.
-# EXPERIMENTAL_INTERNATIONAL=yes
-# LDFLAGS += -lidn
-
 ###############################################################################
 #                 THESE ARE THINGS YOU MIGHT WANT TO SPECIFY                  #
 ###############################################################################
@@ -931,6 +926,17 @@ ZCAT_COMMAND=/usr/bin/zcat
 # SUPPORT_PROXY=yes
 
 
+#------------------------------------------------------------------------------
+# Internationalisation.
+#
+# Uncomment the following to include Internationalisation features.  This is the
+# SMTPUTF8 ESMTP extension, and associated facilities for handling UTF8 domain
+# and localparts, per RFCs 5890, 6530 and 6533.
+# You need to have the IDN library installed.
+
+# SUPPORT_I18N=yes
+# LDFLAGS += -lidn
+
 
 #------------------------------------------------------------------------------
 # Support for authentication via Radius is also available. The Exim support,
diff --git a/src/src/acl.c b/src/src/acl.c
index 911ecfed2..f310a87d3 100644
--- a/src/src/acl.c
+++ b/src/src/acl.c
@@ -208,7 +208,7 @@ enum {
 #endif
   CONTROL_FAKEDEFER,
   CONTROL_FAKEREJECT,
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   CONTROL_UTF8_DOWNCONVERT,
 #endif
   CONTROL_NO_MULTILINE,
@@ -251,7 +251,7 @@ static uschar *controls[] = {
 #endif
   US"fakedefer",
   US"fakereject",
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   US"utf8_downconvert",
 #endif
   US"no_multiline_responses",
@@ -693,7 +693,7 @@ static unsigned int control_forbids[] = {
 #endif
     (1<<ACL_WHERE_MIME)),
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   0,                                               /* utf8_downconvert */
 #endif
 
@@ -750,7 +750,7 @@ static control_def controls_list[] = {
   { US"submission",              CONTROL_SUBMISSION,            TRUE },
   { US"suppress_local_fixups",   CONTROL_SUPPRESS_LOCAL_FIXUPS, FALSE },
   { US"cutthrough_delivery",     CONTROL_CUTTHROUGH_DELIVERY,   FALSE },
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   { US"utf8_downconvert",        CONTROL_UTF8_DOWNCONVERT,      TRUE }
 #endif
   };
@@ -2095,7 +2095,7 @@ else if (verify_sender_address != NULL)
     uschar *save_address_data = deliver_address_data;
 
     sender_vaddr = deliver_make_addr(verify_sender_address, TRUE);
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     if ((sender_vaddr->prop.utf8_msg = message_smtputf8))
       {
       sender_vaddr->prop.utf8_downcvt =       message_utf8_downconvert == 1;
@@ -3402,7 +3402,7 @@ for (; cb != NULL; cb = cb->next)
 	  }
 	return ERROR;
 
-    #ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	case CONTROL_UTF8_DOWNCONVERT:
 	if (*p == '/')
 	  {
@@ -3440,7 +3440,7 @@ for (; cb != NULL; cb = cb->next)
 	  break;
 	  }
 	return ERROR;
-    #endif
+#endif
 
 	}
       break;
@@ -4465,7 +4465,7 @@ if (where == ACL_WHERE_RCPT)
     *log_msgptr = US"defer in percent_hack_domains check";
     return DEFER;
     }
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   if ((addr->prop.utf8_msg = message_smtputf8))
     {
     addr->prop.utf8_downcvt =       message_utf8_downconvert == 1;
diff --git a/src/src/config.h.defaults b/src/src/config.h.defaults
index 6e2c22063..37f47dccf 100644
--- a/src/src/config.h.defaults
+++ b/src/src/config.h.defaults
@@ -131,8 +131,8 @@ it's a default value. */
 #define SPOOL_MODE                 0640
 #define STRING_SPRINTF_BUFFER_SIZE (8192 * 4)
 
-#define SUPPORT_A6
 #define SUPPORT_CRYPTEQ
+#define SUPPORT_I18N
 #define SUPPORT_MAILDIR
 #define SUPPORT_MAILSTORE
 #define SUPPORT_MBX
@@ -177,7 +177,6 @@ it's a default value. */
 #define EXPERIMENTAL_DSN_INFO
 #define EXPERIMENTAL_DMARC
 #define EXPERIMENTAL_EVENT
-#define EXPERIMENTAL_INTERNATIONAL
 #define EXPERIMENTAL_REDIS
 #define EXPERIMENTAL_SPF
 #define EXPERIMENTAL_SRS
diff --git a/src/src/deliver.c b/src/src/deliver.c
index 53712b269..b816b1a77 100644
--- a/src/src/deliver.c
+++ b/src/src/deliver.c
@@ -872,7 +872,7 @@ else
 
 if (LOGGING(sender_on_delivery) || msg)
   s = string_append(s, &size, &ptr, 3, US" F=<",
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     testflag(addr, af_utf8_downcvt)
     ? string_address_utf8_to_alabel(sender_address, NULL)
     :
@@ -5771,7 +5771,7 @@ if (process_recipients != RECIP_IGNORE)
       recipient_item *r = recipients_list + i;
       address_item *new = deliver_make_addr(r->address, FALSE);
       new->prop.errors_address = r->errors_to;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       if ((new->prop.utf8_msg = message_smtputf8))
 	{
 	new->prop.utf8_downcvt =       message_utf8_downconvert == 1;
@@ -7327,7 +7327,7 @@ wording. */
         }
 
       /* output machine readable part */
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       if (message_smtputf8)
 	fprintf(f, "--%s\n"
 	    "Content-type: message/global-delivery-status\n\n"
@@ -7428,7 +7428,7 @@ wording. */
             }
           }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       if (message_smtputf8)
 	fputs(topt & topt_no_body ? "Content-type: message/global-headers\n\n"
 				  : "Content-type: message/global\n\n",
@@ -8074,7 +8074,7 @@ if (!regex_PRDR) regex_PRDR =
   regex_must_compile(US"\\n250[\\s\\-]PRDR(\\s|\\n|$)", FALSE, TRUE);
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 if (!regex_UTF8) regex_UTF8 =
   regex_must_compile(US"\\n250[\\s\\-]SMTPUTF8(\\s|\\n|$)", FALSE, TRUE);
 #endif
diff --git a/src/src/dns.c b/src/src/dns.c
index 9859e8365..02eef25a6 100644
--- a/src/src/dns.c
+++ b/src/src/dns.c
@@ -620,7 +620,7 @@ if (previous != NULL)
   return previous->data.val;
   }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 /* Convert all names to a-label form before doing lookup */
   {
   uschar * alabel;
@@ -851,7 +851,7 @@ for (i = 0; i < 10; i++)
     if (  rr_name
        && Ustrcmp(rr_name, *fully_qualified_name) != 0
        && rr_name[0] != '*'
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
        && (  !string_is_utf8(*fully_qualified_name)
 	  || Ustrcmp(rr_name,
 	       string_domain_utf8_to_alabel(*fully_qualified_name, NULL)) != 0
diff --git a/src/src/exim.c b/src/src/exim.c
index 4e90ca8fd..0fd95dd0c 100644
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -823,6 +823,9 @@ fprintf(f, "Support for:");
 #ifndef DISABLE_DNSSEC
   fprintf(f, " DNSSEC");
 #endif
+#ifdef SUPPORT_I18N
+  fprintf(f, " I18N");
+#endif
 #ifndef DISABLE_OCSP
   fprintf(f, " OCSP");
 #endif
@@ -856,9 +859,6 @@ fprintf(f, "Support for:");
 #ifdef EXPERIMENTAL_DSN_INFO
   fprintf(f, " Experimental_DSN_info");
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
-  fprintf(f, " Experimental_International");
-#endif
 #ifdef EXPERIMENTAL_EVENT
   fprintf(f, " Experimental_Event");
 #endif
@@ -1031,7 +1031,7 @@ DEBUG(D_any) do {
 #ifdef SUPPORT_TLS
   tls_version_report(f);
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   utf8_version_report(f);
 #endif
 
@@ -2561,12 +2561,12 @@ for (i = 1; i < argc; i++)
         if (temp >= argrest && *temp == '.') f_end_dot = TRUE;
         allow_domain_literals = TRUE;
         strip_trailing_dot = TRUE;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	allow_utf8_domains = TRUE;
 #endif
         sender_address = parse_extract_address(argrest, &errmess,
           &dummy_start, &dummy_end, &sender_address_domain, TRUE);
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	message_smtputf8 =  string_is_utf8(sender_address);
 	allow_utf8_domains = FALSE;
 #endif
@@ -3736,7 +3736,7 @@ is equivalent to the ability to modify a setuid binary!
 This needs to happen before we read the main configuration. */
 init_lookup_list();
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 if (running_in_test_harness) smtputf8_advertise_hosts = NULL;
 #endif
 
@@ -5121,7 +5121,7 @@ if (mua_wrapper)
   deliver_drop_privilege = TRUE;
   queue_smtp = FALSE;
   queue_smtp_domains = NULL;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   message_utf8_downconvert = -1;	/* convert-if-needed */
 #endif
   }
@@ -5414,7 +5414,7 @@ while (more)
                 errors_sender_rc : EXIT_FAILURE;
             }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	{
 	BOOL b = allow_utf8_domains;
 	allow_utf8_domains = TRUE;
@@ -5422,7 +5422,7 @@ while (more)
         recipient =
           parse_extract_address(s, &errmess, &start, &end, &domain, FALSE);
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	if (string_is_utf8(recipient))
 	  message_smtputf8 = TRUE;
 	else
diff --git a/src/src/expand.c b/src/src/expand.c
index a5f14364c..55b3d8c29 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -111,7 +111,7 @@ static uschar *item_table[] = {
   US"hash",
   US"hmac",
   US"if",
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   US"imapfolder",
 #endif
   US"length",
@@ -141,7 +141,7 @@ enum {
   EITEM_HASH,
   EITEM_HMAC,
   EITEM_IF,
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   EITEM_IMAPFOLDER,
 #endif
   EITEM_LENGTH,
@@ -173,7 +173,7 @@ static uschar *op_table_underscore[] = {
   US"reverse_ip",
   US"time_eval",
   US"time_interval"
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
  ,US"utf8_domain_from_alabel",
   US"utf8_domain_to_alabel",
   US"utf8_localpart_from_alabel",
@@ -188,7 +188,7 @@ enum {
   EOP_REVERSE_IP,
   EOP_TIME_EVAL,
   EOP_TIME_INTERVAL
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
  ,EOP_UTF8_DOMAIN_FROM_ALABEL,
   EOP_UTF8_DOMAIN_TO_ALABEL,
   EOP_UTF8_LOCALPART_FROM_ALABEL,
@@ -573,7 +573,7 @@ static var_entry var_table[] = {
   { "message_id",          vtype_stringptr,   &message_id },
   { "message_linecount",   vtype_int,         &message_linecount },
   { "message_size",        vtype_int,         &message_size },
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   { "message_smtputf8",    vtype_bool,        &message_smtputf8 },
 #endif
 #ifdef WITH_CONTENT_SCAN
@@ -4095,7 +4095,7 @@ while (*s != 0)
       continue;
       }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     case EITEM_IMAPFOLDER:
       {				/* ${imapfolder {name}{sep]{specials}} */
       uschar *sub_arg[3];
@@ -6757,7 +6757,7 @@ while (*s != 0)
         continue;
         }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       case EOP_UTF8_DOMAIN_TO_ALABEL:
 	{
         uschar * error = NULL;
diff --git a/src/src/functions.h b/src/src/functions.h
index e9f7ab658..edc72bc0d 100644
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -424,7 +424,7 @@ extern BOOL    string_format(uschar *, int, const char *, ...) ALMOST_PRINTF(3,4
 extern uschar *string_format_size(int, uschar *);
 extern int     string_interpret_escape(const uschar **);
 extern int     string_is_ip_address(const uschar *, int *);
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 extern BOOL    string_is_utf8(const uschar *);
 #endif
 extern uschar *string_log_address(address_item *, BOOL, BOOL);
@@ -433,7 +433,7 @@ extern uschar *string_open_failed(int, const char *, ...) PRINTF_FUNCTION(2,3);
 extern const uschar *string_printing2(const uschar *, BOOL);
 extern uschar *string_split_message(uschar *);
 extern uschar *string_unprinting(uschar *);
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 extern uschar *string_address_utf8_to_alabel(const uschar *, uschar **);
 extern uschar *string_domain_alabel_to_utf8(const uschar *, uschar **);
 extern uschar *string_domain_utf8_to_alabel(const uschar *, uschar **);
@@ -474,7 +474,7 @@ extern void    tree_walk(tree_node *, void (*)(uschar*, uschar*, void*), void *)
 #ifdef WITH_CONTENT_SCAN
 extern void    unspool_mbox(void);
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 extern void    utf8_version_report(FILE *);
 #endif
 
diff --git a/src/src/globals.c b/src/src/globals.c
index 6bd33a1a5..9ecb59652 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -178,7 +178,7 @@ BOOL    prdr_requested         = FALSE;
 const pcre *regex_PRDR         = NULL;
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 const pcre *regex_UTF8         = NULL;
 #endif
 
@@ -395,7 +395,7 @@ address_item address_defaults = {
 #ifdef EXPERIMENTAL_SRS
     NULL,               /* srs_sender */
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     FALSE,		/* utf8 */
 #endif
   }
@@ -943,7 +943,7 @@ int     message_linecount      = 0;
 BOOL    message_logs           = TRUE;
 int     message_size           = 0;
 uschar *message_size_limit     = US"50M";
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 BOOL    message_smtputf8       = FALSE;
 int     message_utf8_downconvert = 0;	/* -1 ifneeded; 0 never; 1 always */
 #endif
@@ -1316,7 +1316,7 @@ int     smtp_rlr_limit         = 0;
 int     smtp_rlr_threshold     = INT_MAX;
 BOOL    smtp_use_pipelining    = FALSE;
 BOOL    smtp_use_size          = FALSE;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 uschar *smtputf8_advertise_hosts = US"*";	/* overridden under test-harness */
 #endif
 
diff --git a/src/src/globals.h b/src/src/globals.h
index 899471116..c969214c8 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -576,7 +576,7 @@ extern int     message_linecount;      /* As it says */
 extern BOOL    message_logs;           /* TRUE to write message logs */
 extern int     message_size;           /* Size of message */
 extern uschar *message_size_limit;     /* As it says */
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 extern BOOL    message_smtputf8;       /* Internationalized mail handling */
 extern int     message_utf8_downconvert; /* convert from utf8 */
 const extern pcre *regex_UTF8;         /* For recognizing SMTPUTF8 settings */
@@ -836,7 +836,7 @@ extern int     smtp_rlr_limit;         /* Max delay */
 extern int     smtp_rlr_threshold;     /* Threshold for RCPT rate limit */
 extern BOOL    smtp_use_pipelining;    /* Global for passed connections */
 extern BOOL    smtp_use_size;          /* Global for passed connections */
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 extern uschar *smtputf8_advertise_hosts; /* ingress control */
 #endif
 
diff --git a/src/src/imap_utf7.c b/src/src/imap_utf7.c
index 739e47f41..dcccaeef8 100644
--- a/src/src/imap_utf7.c
+++ b/src/src/imap_utf7.c
@@ -1,6 +1,6 @@
 #include "exim.h"
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 
 uschar *
 imap_utf7_encode(uschar *string, const uschar *charset, uschar sep,
diff --git a/src/src/macros.h b/src/src/macros.h
index 1cec4abd5..66abffa37 100644
--- a/src/src/macros.h
+++ b/src/src/macros.h
@@ -533,7 +533,7 @@ to conflict with system errno values. */
 #define ERRNO_PROXYFAIL      (-47)   /* Negotiation failed for proxy configured host */
 #define ERRNO_AUTHPROB       (-48)   /* Authenticator "other" failure */
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 # define ERRNO_UTF8_FWD      (-49)   /* target not supporting SMTPUTF8 */
 #endif
 
diff --git a/src/src/queue.c b/src/src/queue.c
index dc1c320c7..bf62aea88 100644
--- a/src/src/queue.c
+++ b/src/src/queue.c
@@ -1274,7 +1274,7 @@ switch(action)
       {
       if (action == MSG_ADD_RECIPIENT)
         {
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	if (string_is_utf8(recipient)) allow_utf8_domains = message_smtputf8 = TRUE;
 #endif
         receive_add_recipient(recipient, -1);
@@ -1300,7 +1300,7 @@ switch(action)
         }
       else  /* MSG_EDIT_SENDER */
         {
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	if (string_is_utf8(recipient)) allow_utf8_domains = message_smtputf8 = TRUE;
 #endif
         sender_address = recipient;
diff --git a/src/src/readconf.c b/src/src/readconf.c
index 9b0b26e42..30ff757ac 100644
--- a/src/src/readconf.c
+++ b/src/src/readconf.c
@@ -413,7 +413,7 @@ static optionlist optionlist_config[] = {
   { "smtp_receive_timeout",     opt_func,        &fn_smtp_receive_timeout },
   { "smtp_reserve_hosts",       opt_stringptr,   &smtp_reserve_hosts },
   { "smtp_return_error_details",opt_bool,        &smtp_return_error_details },
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   { "smtputf8_advertise_hosts", opt_stringptr,   &smtputf8_advertise_hosts },
 #endif
 #ifdef WITH_CONTENT_SCAN
diff --git a/src/src/receive.c b/src/src/receive.c
index dc228d921..585cb9025 100644
--- a/src/src/receive.c
+++ b/src/src/receive.c
@@ -2303,7 +2303,7 @@ if (extract_recip)
         for (p = s; p < ss; p++) if (*p != '\n') *pp++ = *p;
         *pp = 0;
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	{
 	BOOL b = allow_utf8_domains;
 	allow_utf8_domains = TRUE;
@@ -2311,7 +2311,7 @@ if (extract_recip)
         recipient = parse_extract_address(recipient, &errmess, &start, &end,
           &domain, FALSE);
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	if (string_is_utf8(recipient))
 	  message_smtputf8 = TRUE;
 	else
diff --git a/src/src/routers/redirect.c b/src/src/routers/redirect.c
index 371377317..7bbaa82e4 100644
--- a/src/src/routers/redirect.c
+++ b/src/src/routers/redirect.c
@@ -451,7 +451,7 @@ while (generated != NULL)
       }
     }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     next->prop.utf8_msg = string_is_utf8(next->address)
       || (sender_address && string_is_utf8(sender_address));
 #endif
@@ -475,7 +475,7 @@ while (generated != NULL)
     else
       debug_printf("gid=unset ");
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     if (next->prop.utf8_msg) debug_printf("utf8 ");
 #endif
 
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index 86b0d21cf..3fce125d3 100644
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -135,7 +135,7 @@ static BOOL rcpt_smtp_response_same;
 static BOOL rcpt_in_progress;
 static int  nonmail_command_count;
 static BOOL smtp_exit_function_called = 0;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 static BOOL smtputf8_advertised;
 #endif
 static int  synprot_error_count;
@@ -239,7 +239,7 @@ enum {
   ENV_MAIL_OPT_PRDR,
 #endif
   ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   ENV_MAIL_OPT_UTF8,
 #endif
   };
@@ -258,7 +258,7 @@ static env_mail_type_t env_mail_type_list[] = {
 #endif
     { US"RET",    ENV_MAIL_OPT_RET,    TRUE },
     { US"ENVID",  ENV_MAIL_OPT_ENVID,  TRUE },
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     { US"SMTPUTF8",ENV_MAIL_OPT_UTF8,  FALSE },		/* rfc6531 */
 #endif
     /* keep this the last entry */
@@ -1544,7 +1544,7 @@ spf_received = NULL;
 spf_result = NULL;
 spf_smtp_comment = NULL;
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 message_smtputf8 = FALSE;
 #endif
 body_linecount = body_zerocount = 0;
@@ -1882,7 +1882,7 @@ tls_in.ocsp = OCSP_NOT_REQ;
 tls_advertised = FALSE;
 #endif
 dsn_advertised = FALSE;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 smtputf8_advertised = FALSE;
 #endif
 
@@ -3577,7 +3577,7 @@ while (done <= 0)
     tls_advertised = FALSE;
 #endif
     dsn_advertised = FALSE;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     smtputf8_advertised = FALSE;
 #endif
 
@@ -3771,7 +3771,7 @@ while (done <= 0)
 	}
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       if (  accept_8bitmime
          && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
 	{
@@ -4054,7 +4054,7 @@ while (done <= 0)
           break;
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
         case ENV_MAIL_OPT_UTF8:
 	  if (smtputf8_advertised)
 	    {
diff --git a/src/src/spool_in.c b/src/src/spool_in.c
index a7095bbaa..59192ef30 100644
--- a/src/src/spool_in.c
+++ b/src/src/spool_in.c
@@ -303,7 +303,7 @@ spam_score = NULL;
 spam_score_int = NULL;
 #endif
 
-#if defined(EXPERIMENTAL_INTERNATIONAL) && !defined(COMPILE_UTILITY)
+#if defined(SUPPORT_I18N) && !defined(COMPILE_UTILITY)
 message_smtputf8 = FALSE;
 message_utf8_downconvert = 0;
 #endif
@@ -582,7 +582,7 @@ for (;;)
     else if (Ustrncmp(p, "pam_score_int ", 14) == 0)
       spam_score_int = string_copy(big_buffer + 16);
 #endif
-#if defined(EXPERIMENTAL_INTERNATIONAL) && !defined(COMPILE_UTILITY)
+#if defined(SUPPORT_I18N) && !defined(COMPILE_UTILITY)
     else if (Ustrncmp(p, "mtputf8", 7) == 0)
       message_smtputf8 = TRUE;
 #endif
@@ -609,7 +609,7 @@ for (;;)
     break;
 #endif
 
-#if defined(EXPERIMENTAL_INTERNATIONAL) && !defined(COMPILE_UTILITY)
+#if defined(SUPPORT_I18N) && !defined(COMPILE_UTILITY)
     case 'u':
     if (Ustrncmp(p, "tf8_downcvt", 11) == 0)
       message_utf8_downconvert = 1;
diff --git a/src/src/spool_out.c b/src/src/spool_out.c
index e7a6a6535..8d0ee7c71 100644
--- a/src/src/spool_out.c
+++ b/src/src/spool_out.c
@@ -247,7 +247,7 @@ if (tls_in.ourcert)
 if (tls_in.ocsp)	 fprintf(f, "-tls_ocsp %d\n",   tls_in.ocsp);
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 if (message_smtputf8)
   {
   fprintf(f, "-smtputf8\n");
diff --git a/src/src/string.c b/src/src/string.c
index b76b0abbc..d01383f65 100644
--- a/src/src/string.c
+++ b/src/src/string.c
@@ -1553,7 +1553,7 @@ uschar * s;
 s = addr->prefix;
 if (testflag(addr, af_include_affixes) && s)
   {
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   if (testflag(addr, af_utf8_downcvt))
     s = string_localpart_utf8_to_alabel(s, NULL);
 #endif
@@ -1561,7 +1561,7 @@ if (testflag(addr, af_include_affixes) && s)
   }
 
 s = addr->local_part;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 if (testflag(addr, af_utf8_downcvt))
   s = string_localpart_utf8_to_alabel(s, NULL);
 #endif
@@ -1570,7 +1570,7 @@ yield = string_cat(yield, sizeptr, ptrptr, s, Ustrlen(s));
 s = addr->suffix;
 if (testflag(addr, af_include_affixes) && s)
   {
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   if (testflag(addr, af_utf8_downcvt))
     s = string_localpart_utf8_to_alabel(s, NULL);
 #endif
@@ -1641,7 +1641,7 @@ else
     yield = string_get_localpart(addr, yield, &size, &ptr);
     yield = string_cat(yield, &size, &ptr, US"@", 1);
     s = addr->domain;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     if (testflag(addr, af_utf8_downcvt))
       s = string_localpart_utf8_to_alabel(s, NULL);
 #endif
diff --git a/src/src/structs.h b/src/src/structs.h
index 713702ea5..5fe8551cd 100644
--- a/src/src/structs.h
+++ b/src/src/structs.h
@@ -467,7 +467,7 @@ typedef struct address_item_propagated {
   #ifdef EXPERIMENTAL_SRS
   uschar *srs_sender;             /* Change return path when delivering */
   #endif
-  #ifdef EXPERIMENTAL_INTERNATIONAL
+  #ifdef SUPPORT_I18N
   BOOL    utf8_msg:1;		  /* requires SMTPUTF8 processing */
   BOOL	  utf8_downcvt:1;	  /* mandatory downconvert on delivery */
   BOOL	  utf8_downcvt_maybe:1;	  /* optional downconvert on delivery */
@@ -510,7 +510,7 @@ typedef struct address_item_propagated {
 #ifdef EXPERIMENTAL_DANE
 # define af_dane_verified      0x20000000 /* TLS cert verify done with DANE */
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 # define af_utf8_downcvt       0x40000000 /* downconvert was done for delivery */
 #endif
 
diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c
index c316d0a24..c2f073833 100644
--- a/src/src/tls-gnu.c
+++ b/src/src/tls-gnu.c
@@ -1834,7 +1834,7 @@ tls_client_setup_hostname_checks(host_item * host, exim_gnutls_state_st * state,
 if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK)
   {
   state->exp_tls_verify_cert_hostnames =
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     string_domain_utf8_to_alabel(host->name, NULL);
 #else
     host->name;
diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c
index c68b25d83..704522b50 100644
--- a/src/src/tls-openssl.c
+++ b/src/src/tls-openssl.c
@@ -1860,7 +1860,7 @@ if ((rc = setup_certs(ctx, ob->tls_verify_certificates,
 if (verify_check_given_host(&ob->tls_verify_cert_hostnames, host) == OK)
   {
   cbinfo->verify_cert_hostnames =
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     string_domain_utf8_to_alabel(host->name, NULL);
 #else
     host->name;
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index 30facda00..c53ae2386 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -596,7 +596,7 @@ if (*errno_value == ERRNO_WRITEINCOMPLETE)
   return FALSE;
   }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 /* Handle lack of advertised SMTPUTF8, for international message */
 if (*errno_value == ERRNO_UTF8_FWD)
   {
@@ -1403,7 +1403,7 @@ BOOL pass_message = FALSE;
 BOOL prdr_offered = FALSE;
 BOOL prdr_active;
 #endif
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 BOOL utf8_needed = FALSE;
 BOOL utf8_offered = FALSE;
 #endif
@@ -1535,7 +1535,7 @@ if (continue_hostname == NULL)
   delayed till here so that $sending_interface and $sending_port are set. */
 
   helo_data = expand_string(ob->helo_data);
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   if (helo_data)
     {
     uschar * errstr = NULL;
@@ -1709,7 +1709,7 @@ goto SEND_QUIT;
     {DEBUG(D_transport) debug_printf("PRDR usable\n");}
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   if (addrlist->prop.utf8_msg)
     {
     utf8_needed =  !addrlist->prop.utf8_downcvt
@@ -1950,7 +1950,7 @@ if (continue_hostname == NULL
     {DEBUG(D_transport) debug_printf("PRDR usable\n");}
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   if (addrlist->prop.utf8_msg)
     utf8_offered = esmtp
       && pcre_exec(regex_UTF8, NULL, CS buffer, Ustrlen(buffer), 0,
@@ -1983,7 +1983,7 @@ message-specific. */
 
 setting_up = FALSE;
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 /* If this is an international message we need the host to speak SMTPUTF8 */
 if (utf8_needed && !utf8_offered)
   {
@@ -2068,7 +2068,7 @@ if (prdr_offered)
   }
 #endif
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 if (addrlist->prop.utf8_msg && !addrlist->prop.utf8_downcvt && utf8_offered)
   sprintf(CS p, " SMTPUTF8"), p += 9;
 #endif
@@ -2128,7 +2128,7 @@ pending_MAIL = TRUE;     /* The block starts with MAIL */
 
   {
   uschar * s = return_path;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   uschar * errstr = NULL;
 
   /* If we must downconvert, do the from-address here.  Remember we had to
@@ -2239,7 +2239,7 @@ for (addr = first_addr;
 
   rcpt_addr = transport_rcpt_address(addr, tblock->rcpt_include_affixes);
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
   {
   uschar * dummy_errstr;
   if (  testflag(addrlist, af_utf8_downcvt)
@@ -2679,7 +2679,7 @@ if (!ok)
 
     switch(save_errno)
       {
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       case ERRNO_UTF8_FWD:
         code = '5';
       /*FALLTHROUGH*/
diff --git a/src/src/utf8.c b/src/src/utf8.c
index 8a7cf38a3..84ad1dc18 100644
--- a/src/src/utf8.c
+++ b/src/src/utf8.c
@@ -8,7 +8,7 @@
 
 #include "exim.h"
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 
 #include <idna.h>
 #include <punycode.h>
diff --git a/src/src/verify.c b/src/src/verify.c
index 6c228abbf..17c99d174 100644
--- a/src/src/verify.c
+++ b/src/src/verify.c
@@ -174,7 +174,7 @@ dbdata_callout_cache new_domain_record;
 dbdata_callout_cache_address new_address_record;
 host_item *host;
 time_t callout_start_time;
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 BOOL utf8_offered = FALSE;
 #endif
 
@@ -924,7 +924,7 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
         }
       }
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
     else if (  addr->prop.utf8_msg
 	    && !addr->prop.utf8_downcvt
 	    && !(  esmtp
@@ -976,7 +976,7 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
 
     /* Send the MAIL command */
         (smtp_write_command(&outblock, FALSE,
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	  addr->prop.utf8_msg && !addr->prop.utf8_downcvt
 	  ? "MAIL FROM:<%s>%s SMTPUTF8\r\n"
 	  :
@@ -1022,7 +1022,7 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
       {
       const uschar * rcpt_domain = addr->domain;
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       uschar * errstr = NULL;
       if (  testflag(addr, af_utf8_downcvt)
 	 && (rcpt_domain = string_domain_utf8_to_alabel(rcpt_domain,
@@ -1084,7 +1084,7 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
               '2', callout) &&
 
             smtp_write_command(&outblock, FALSE,
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	      addr->prop.utf8_msg && !addr->prop.utf8_downcvt
 	      ? "MAIL FROM:<%s> SMTPUTF8\r\n"
 	      :
@@ -1124,7 +1124,7 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
 	uschar * rcpt = transport_rcpt_address(addr,
               addr->transport ? addr->transport->rcpt_include_affixes : FALSE);
 
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
 	/*XXX should the conversion be moved into transport_rcpt_address() ? */
 	uschar * dummy_errstr = NULL;
 	if (  testflag(addr, af_utf8_downcvt)
@@ -1229,7 +1229,7 @@ can do it there for the non-rcpt-verify case.  For this we keep an addresscount.
         HDEBUG(D_verify) debug_printf("SMTP timeout\n");
         send_quit = FALSE;
         }
-#ifdef EXPERIMENTAL_INTERNATIONAL
+#ifdef SUPPORT_I18N
       else if (errno == ERRNO_UTF8_FWD)
 	{
 	extern int acl_where;	/* src/acl.c */
diff --git a/test/scripts/4200-International/REQUIRES b/test/scripts/4200-International/REQUIRES
index c66f68046..3024f81eb 100644
--- a/test/scripts/4200-International/REQUIRES
+++ b/test/scripts/4200-International/REQUIRES
@@ -1 +1 @@
-support Experimental_International
+support I18N
diff --git a/test/scripts/4210-GnuTLS-International/REQUIRES b/test/scripts/4210-GnuTLS-International/REQUIRES
index d75e95074..09843a4cc 100644
--- a/test/scripts/4210-GnuTLS-International/REQUIRES
+++ b/test/scripts/4210-GnuTLS-International/REQUIRES
@@ -1,2 +1,2 @@
-support Experimental_International
+support I18N
 support GnuTLS
diff --git a/test/scripts/4220-OpenSSL-International/REQUIRES b/test/scripts/4220-OpenSSL-International/REQUIRES
index 74b249f4c..ada714079 100644
--- a/test/scripts/4220-OpenSSL-International/REQUIRES
+++ b/test/scripts/4220-OpenSSL-International/REQUIRES
@@ -1,2 +1,2 @@
-support Experimental_International
+support I18N
 support OpenSSL