Move DSN support to mainline

Affects bug 893

18 files changed, 22 insertions, 221 deletions

diff --git a/src/exim_monitor/em_globals.c b/src/exim_monitor/em_globals.c
index 918659d98..3277012f0 100644
--- a/src/exim_monitor/em_globals.c
+++ b/src/exim_monitor/em_globals.c
@@ -145,10 +145,8 @@ BOOL    dkim_disable_verify      = FALSE;
 
 BOOL    dont_deliver           = FALSE;
 
-#ifdef EXPERIMENTAL_DSN
 int     dsn_ret                = 0;
 uschar *dsn_envid              = NULL;
-#endif
 
 #ifdef WITH_CONTENT_SCAN
 int     fake_response          = OK;
diff --git a/src/src/EDITME b/src/src/EDITME
index 4a290a4bc..353dde3ee 100644
--- a/src/src/EDITME
+++ b/src/src/EDITME
@@ -491,9 +491,6 @@ EXIM_MONITOR=eximon.bin
 # ownership
 # EXPERIMENTAL_CERTNAMES=yes
 
-# Uncomment the following line to add DSN support
-# EXPERIMENTAL_DSN=yes
-
 # Uncomment the following line to add DANE support
 # EXPERIMENTAL_DANE=yes
 
diff --git a/src/src/config.h.defaults b/src/src/config.h.defaults
index ec4322c70..e339bdf9e 100644
--- a/src/src/config.h.defaults
+++ b/src/src/config.h.defaults
@@ -170,7 +170,6 @@ it's a default value. */
 #define EXPERIMENTAL_DANE
 #define EXPERIMENTAL_DCC
 #define EXPERIMENTAL_DMARC
-#define EXPERIMENTAL_DSN
 #define EXPERIMENTAL_PROXY
 #define EXPERIMENTAL_REDIS
 #define EXPERIMENTAL_SPF
diff --git a/src/src/deliver.c b/src/src/deliver.c
index 5000f1cbc..462aaf49d 100644
--- a/src/src/deliver.c
+++ b/src/src/deliver.c
@@ -63,10 +63,8 @@ static address_item *addr_new = NULL;
 static address_item *addr_remote = NULL;
 static address_item *addr_route = NULL;
 static address_item *addr_succeed = NULL;
-#ifdef EXPERIMENTAL_DSN
 static address_item *addr_dsntmp = NULL;
 static address_item *addr_senddsn = NULL;
-#endif
 
 static FILE *message_log = NULL;
 static BOOL update_spool;
@@ -3166,14 +3164,12 @@ while (!done)
     break;
 #endif
 
-#ifdef EXPERIMENTAL_DSN
     case 'D':
     if (addr == NULL) goto ADDR_MISMATCH;
     memcpy(&(addr->dsn_aware), ptr, sizeof(addr->dsn_aware));
     ptr += sizeof(addr->dsn_aware);
     DEBUG(D_deliver) debug_printf("DSN read: addr->dsn_aware = %d\n", addr->dsn_aware);
     break;
-#endif
 
     case 'A':
     if (addr == NULL)
@@ -4370,11 +4366,9 @@ for (delivery_count = 0; addr_remote != NULL; delivery_count++)
 	rmt_dlv_checked_write(fd, 'P', '0', NULL, 0);
 #endif
 
-#ifdef EXPERIMENTAL_DSN
       memcpy(big_buffer, &addr->dsn_aware, sizeof(addr->dsn_aware));
       rmt_dlv_checked_write(fd, 'D', '0', big_buffer, sizeof(addr->dsn_aware));
       DEBUG(D_deliver) debug_printf("DSN write: addr->dsn_aware = %d\n", addr->dsn_aware);
-#endif
 
       /* Retry information: for most success cases this will be null. */
 
@@ -4814,7 +4808,6 @@ while (*s != 0)
 }
 
 
-#ifdef EXPERIMENTAL_DSN
 /***********************************************************
 *         Print Diagnostic-Code for an address             *
 ************************************************************/
@@ -4863,7 +4856,6 @@ while (*s)
 
 fputc('\n', f);
 }
-#endif  /* EXPERIMENTAL_DSN */
 
 
 /*************************************************
@@ -5577,13 +5569,11 @@ if (process_recipients != RECIP_IGNORE)
       if (r->pno >= 0)
         new->onetime_parent = recipients_list[r->pno].address;
 
-#ifdef EXPERIMENTAL_DSN
       /* If DSN support is enabled, set the dsn flags and the original receipt 
          to be passed on to other DSN enabled MTAs */
       new->dsn_flags = r->dsn_flags & rf_dsnflags;
       new->dsn_orcpt = r->orcpt;
       DEBUG(D_deliver) debug_printf("DSN: set orcpt: %s  flags: %d\n", new->dsn_orcpt, new->dsn_flags);
-#endif
 
       switch (process_recipients)
         {
@@ -6548,11 +6538,9 @@ if (addr_remote != NULL)
     regex_must_compile(US"\\n250[\\s\\-]PRDR(\\s|\\n|$)", FALSE, TRUE);
 #endif
 
-#ifdef EXPERIMENTAL_DSN
   /* Set the regex to check for DSN support on remote MTA */
   if (regex_DSN == NULL) regex_DSN  =
     regex_must_compile(US"\\n250[\\s\\-]DSN(\\s|\\n|$)", FALSE, TRUE);
-#endif
 
   /* Now sort the addresses if required, and do the deliveries. The yield of
   do_remote_deliveries is FALSE when mua_wrapper is set and all addresses
@@ -6661,7 +6649,6 @@ prevents actual delivery. */
 
 else if (!dont_deliver) retry_update(&addr_defer, &addr_failed, &addr_succeed);
 
-#ifdef EXPERIMENTAL_DSN
 /* Send DSN for successful messages */
 addr_dsntmp = addr_succeed;
 addr_senddsn = NULL;
@@ -6820,7 +6807,6 @@ if (addr_senddsn != NULL)
     rc = child_close(pid, 0);     /* Waits for child to close, no timeout */
     }
   }
-#endif	/*EXPERIMENTAL_DSN*/
 
 /* If any addresses failed, we must send a message to somebody, unless
 af_ignore_error is set, in which case no action is taken. It is possible for
@@ -6879,11 +6865,9 @@ while (addr_failed != NULL)
   it from the list, throw away any saved message file, log it, and
   mark the recipient done. */
 
-  if (testflag(addr_failed, af_ignore_error)
-#ifdef EXPERIMENTAL_DSN
-      || (((addr_failed->dsn_flags & rf_dsnflags) != 0)
-         && ((addr_failed->dsn_flags & rf_notify_failure) != rf_notify_failure))
-#endif
+  if (  testflag(addr_failed, af_ignore_error)
+     || (  ((addr_failed->dsn_flags & rf_dsnflags) != 0)
+        && ((addr_failed->dsn_flags & rf_notify_failure) != rf_notify_failure))
      )
   {
     addr = addr_failed;
@@ -6937,12 +6921,10 @@ while (addr_failed != NULL)
       BOOL to_sender = strcmpic(sender_address, bounce_recipient) == 0;
       int max = (bounce_return_size_limit/DELIVER_IN_BUFFER_SIZE + 1) *
         DELIVER_IN_BUFFER_SIZE;
-#ifdef EXPERIMENTAL_DSN
       uschar * bound;
       uschar *dsnlimitmsg;
       uschar *dsnnotifyhdr;
       int topt;
-#endif
 
       DEBUG(D_deliver)
         debug_printf("sending error message to: %s\n", bounce_recipient);
@@ -6996,7 +6978,6 @@ while (addr_failed != NULL)
       moan_write_from(f);
       fprintf(f, "To: %s\n", bounce_recipient);
 
-#ifdef EXPERIMENTAL_DSN
       /* generate boundary string and output MIME-Headers */
       bound = string_sprintf(TIME_T_FMT "-eximdsn-%d", time(NULL), rand());
 
@@ -7004,7 +6985,6 @@ while (addr_failed != NULL)
 	    " report-type=delivery-status; boundary=%s\n"
 	  "MIME-Version: 1.0\n",
 	bound);
-#endif
 
       /* Open a template file if one is provided. Log failure to open, but
       carry on - default texts will be used. */
@@ -7029,12 +7009,10 @@ while (addr_failed != NULL)
         fprintf(f, "Subject: Mail delivery failed%s\n\n",
           to_sender? ": returning message to sender" : "");
 
-#ifdef EXPERIMENTAL_DSN
       /* output human readable part as text/plain section */
       fprintf(f, "--%s\n"
 	  "Content-type: text/plain; charset=us-ascii\n\n",
 	bound);
-#endif
 
       if ((emf_text = next_emf(emf, US"intro")))
 	fprintf(f, "%s", CS emf_text);
@@ -7161,7 +7139,6 @@ wording. */
 	fputc('\n', f);
         }
 
-#ifdef EXPERIMENTAL_DSN
       /* output machine readable part */
       fprintf(f, "--%s\n"
 	  "Content-type: message/delivery-status\n\n"
@@ -7192,7 +7169,6 @@ wording. */
           print_dsn_diagnostic_code(addr, f);
           }
         }
-#endif
 
       /* Now copy the message, trying to give an intelligible comment if
       it is too long for it all to be copied. The limit isn't strictly
@@ -7201,65 +7177,6 @@ wording. */
 
       emf_text = next_emf(emf, US"copy");
 
-#ifndef EXPERIMENTAL_DSN
-      if (bounce_return_message)
-        {
-        int topt = topt_add_return_path;
-        if (!bounce_return_body) topt |= topt_no_body;
-
-        if (emf_text)
-	  fprintf(f, "%s", CS emf_text);
-	else
-          {
-          if (bounce_return_body) fprintf(f,
-"------ This is a copy of the message, including all the headers. ------\n");
-          else fprintf(f,
-"------ This is a copy of the message's headers. ------\n");
-          }
-
-        /* While reading the "truncated" message, set return_size_limit to
-        the actual max testing value, rounded. We need to read the message
-        whether we are going to use it or not. */
-
-          {
-          int temp = bounce_return_size_limit;
-          bounce_return_size_limit = (max/1000)*1000;
-          emf_text = next_emf(emf, US"truncated");
-          bounce_return_size_limit = temp;
-          }
-
-        if (bounce_return_body && bounce_return_size_limit > 0)
-          {
-          struct stat statbuf;
-          if (fstat(deliver_datafile, &statbuf) == 0 && statbuf.st_size > max)
-	    {
-            if (emf_text)
-	      fprintf(f, "%s", CS emf_text);
-	    else
-              fprintf(f,
-"------ The body of the message is " OFF_T_FMT " characters long; only the first\n"
-"------ %d or so are included here.\n", statbuf.st_size, max);
-	    }
-          }
-
-	fputc('\n', f);
-        fflush(f);
-
-        transport_filter_argv = NULL;   /* Just in case */
-        return_path = sender_address;   /* In case not previously set */
-        transport_write_message(NULL, fileno(f), topt,
-          bounce_return_size_limit, NULL, NULL, NULL, NULL, NULL, 0);
-        }
-
-      /* Write final text and close the template file if one is open */
-
-      if (emf)
-        {
-        if ((emf_text = next_emf(emf, US"final")))
-	  fprintf(f, "%s", CS emf_text);
-        (void)fclose(emf);
-        }
-#else
       /* add message body
          we ignore the intro text from template and add 
          the text for bounce_return_size_limit at the end.
@@ -7317,7 +7234,6 @@ wording. */
         (void)fclose(emf);
  
       fprintf(f, "\n--%s--\n", bound);
-#endif	/*EXPERIMENTAL_DSN*/
 
       /* Close the file, which should send an EOF to the child process
       that is receiving the message. Wait for it to finish. */
@@ -7552,15 +7468,18 @@ else if (addr_defer != (address_item *)(+1))
   is not sent. Another attempt will be made at the next delivery attempt (if
   it also defers). */
 
-  if (!queue_2stage && delivery_attempted &&
-#ifdef EXPERIMENTAL_DSN
-      (((addr_defer->dsn_flags & rf_dsnflags) == 0) ||
-       (addr_defer->dsn_flags & rf_notify_delay) == rf_notify_delay) &&
-#endif
-      delay_warning[1] > 0 && sender_address[0] != 0 &&
-       (delay_warning_condition == NULL ||
-          expand_check_condition(delay_warning_condition,
-            US"delay_warning", US"option")))
+  if (  !queue_2stage
+     && delivery_attempted
+     && (  ((addr_defer->dsn_flags & rf_dsnflags) == 0)
+        || (addr_defer->dsn_flags & rf_notify_delay) == rf_notify_delay
+	)
+     && delay_warning[1] > 0
+     && sender_address[0] != 0
+     && (  delay_warning_condition == NULL
+        || expand_check_condition(delay_warning_condition,
+            US"delay_warning", US"option")
+	)
+     )
     {
     int count;
     int show_time;
@@ -7621,9 +7540,7 @@ else if (addr_defer != (address_item *)(+1))
         uschar *wmf_text;
         FILE *wmf = NULL;
         FILE *f = fdopen(fd, "wb");
-#ifdef EXPERIMENTAL_DSN
 	uschar * bound;
-#endif
 
         if (warn_message_file)
           {
@@ -7644,7 +7561,6 @@ else if (addr_defer != (address_item *)(+1))
         moan_write_from(f);
         fprintf(f, "To: %s\n", recipients);
 
-#ifdef EXPERIMENTAL_DSN
         /* generated boundary string and output MIME-Headers */
         bound = string_sprintf(TIME_T_FMT "-eximdsn-%d", time(NULL), rand());
 
@@ -7652,7 +7568,6 @@ else if (addr_defer != (address_item *)(+1))
 	    " report-type=delivery-status; boundary=%s\n"
 	    "MIME-Version: 1.0\n",
 	  bound);
-#endif
 
         if ((wmf_text = next_emf(wmf, US"header")))
           fprintf(f, "%s\n", wmf_text);
@@ -7660,12 +7575,10 @@ else if (addr_defer != (address_item *)(+1))
           fprintf(f, "Subject: Warning: message %s delayed %s\n\n",
             message_id, warnmsg_delay);
 
-#ifdef EXPERIMENTAL_DSN
         /* output human readable part as text/plain section */
         fprintf(f, "--%s\n"
 	    "Content-type: text/plain; charset=us-ascii\n\n",
 	  bound);
-#endif
 
         if ((wmf_text = next_emf(wmf, US"intro")))
 	  fprintf(f, "%s", CS wmf_text);
@@ -7704,10 +7617,8 @@ else if (addr_defer != (address_item *)(+1))
 
         /* List the addresses, with error information if allowed */
 
-#ifdef EXPERIMENTAL_DSN
         /* store addr_defer for machine readable part */
         address_item *addr_dsndefer = addr_defer;
-#endif
         fputc('\n', f);
         while (addr_defer)
           {
@@ -7736,7 +7647,6 @@ else if (addr_defer != (address_item *)(+1))
 "and when that happens, the message will be returned to you.\n");
           }
 
-#ifdef EXPERIMENTAL_DSN
         /* output machine readable part */
         fprintf(f, "\n--%s\n"
 	    "Content-type: message/delivery-status\n\n"
@@ -7789,7 +7699,6 @@ else if (addr_defer != (address_item *)(+1))
         fprintf(f,"\n--%s--\n", bound);
 
         fflush(f);
-#endif	/*EXPERIMENTAL_DSN*/
 
         /* Close and wait for child process to complete, without a timeout.
         If there's an error, don't update the count. */
diff --git a/src/src/exim.c b/src/src/exim.c
index e0b754666..33c2a90bd 100644
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -853,9 +853,6 @@ fprintf(f, "Support for:");
 #ifdef EXPERIMENTAL_REDIS
   fprintf(f, " Experimental_Redis");
 #endif
-#ifdef EXPERIMENTAL_DSN
-  fprintf(f, " Experimental_DSN");
-#endif
 fprintf(f, "\n");
 
 fprintf(f, "Lookups (built-in):");
@@ -2678,7 +2675,6 @@ for (i = 1; i < argc; i++)
       break;
       }
 
-    #ifdef EXPERIMENTAL_DSN
     /* -MCD: set the smtp_use_dsn flag; this indicates that the host
        that exim is connected to supports the esmtp extension DSN */
     else if (Ustrcmp(argrest, "CD") == 0)
@@ -2686,7 +2682,6 @@ for (i = 1; i < argc; i++)
       smtp_use_dsn = TRUE;
       break;
       }
-    #endif
 
     /* -MCP: set the smtp_use_pipelining flag; this is useful only when
     it preceded -MC (see above) */
diff --git a/src/src/globals.c b/src/src/globals.c
index 8cdfb0ee0..85d2e5c36 100644
--- a/src/src/globals.c
+++ b/src/src/globals.c
@@ -134,13 +134,11 @@ tls_support tls_out = {
  0     /* tls_ocsp */
 };
 
-#ifdef EXPERIMENTAL_DSN
 uschar *dsn_envid              = NULL;
 int     dsn_ret                = 0;
 const pcre  *regex_DSN         = NULL;
 BOOL    smtp_use_dsn           = FALSE;
 uschar *dsn_advertise_hosts    = NULL;
-#endif
 
 #ifdef SUPPORT_TLS
 BOOL    gnutls_compat_mode     = FALSE;
@@ -361,11 +359,9 @@ address_item address_defaults = {
   NULL,			/* authenticator */
   NULL,			/* auth_id */
   NULL,			/* auth_sndr */
-  #ifdef EXPERIMENTAL_DSN
   NULL,                 /* dsn_orcpt */
   0,                    /* dsn_flags */
   0,                    /* dsn_aware */
-  #endif
   (uid_t)(-1),          /* uid */
   (gid_t)(-1),          /* gid */
   0,                    /* flags */
@@ -1149,9 +1145,7 @@ router_instance  router_defaults = {
     TRUE,                      /* verify_sender */
     FALSE,                     /* uid_set */
     FALSE,                     /* unseen */
-#ifdef EXPERIMENTAL_DSN
     FALSE,                     /* dsn_lasthop */
-#endif
 
     self_freeze,               /* self_code */
     (uid_t)(-1),               /* uid */
diff --git a/src/src/globals.h b/src/src/globals.h
index 5746167dd..7ca07d56c 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -130,13 +130,11 @@ extern uschar *tls_verify_certificates;/* Path for certificates to check */
 extern uschar *tls_verify_hosts;       /* Mandatory client verification */
 #endif
 
-#ifdef EXPERIMENTAL_DSN
 extern uschar  *dsn_envid;             /* DSN envid string */
 extern int      dsn_ret;               /* DSN ret type*/
 extern const pcre  *regex_DSN;         /* For recognizing DSN settings */
 extern BOOL     smtp_use_dsn;          /* Global for passed connections */
 extern uschar  *dsn_advertise_hosts;   /* host for which TLS is advertised */
-#endif
 
 /* Input-reading functions for messages, so we can use special ones for
 incoming TCP/IP. */
diff --git a/src/src/local_scan.h b/src/src/local_scan.h
index 6df601af4..5bd335eca 100644
--- a/src/src/local_scan.h
+++ b/src/src/local_scan.h
@@ -128,10 +128,8 @@ typedef struct recipient_item {
   uschar *address;              /* the recipient address */
   int     pno;                  /* parent number for "one_time" alias, or -1 */
   uschar *errors_to;            /* the errors_to address or NULL */
-#ifdef EXPERIMENTAL_DSN
   uschar *orcpt;                /* DSN orcpt */
   int     dsn_flags;            /* DSN flags */
-#endif
 #ifdef EXPERIMENTAL_BRIGHTMAIL
   uschar *bmi_optin;
 #endif
diff --git a/src/src/macros.h b/src/src/macros.h
index 67e804f56..2a49c1d10 100644
--- a/src/src/macros.h
+++ b/src/src/macros.h
@@ -793,7 +793,6 @@ enum {
 #define topt_no_body            0x040  /* Omit body */
 #define topt_escape_headers     0x080  /* Apply escape check to headers */
 
-#ifdef EXPERIMENTAL_DSN
 /* Flags for recipient_block, used in DSN support */
 
 #define rf_dsnlasthop           0x01  /* Do not propagate DSN any further */
@@ -814,7 +813,6 @@ enum {
 #define dsn_support_yes         1
 #define dsn_support_no          2
 
-#endif
 
 /* Codes for the host_find_failed and host_all_ignored options. */
 
diff --git a/src/src/readconf.c b/src/src/readconf.c
index df4cbb2fd..0b3778054 100644
--- a/src/src/readconf.c
+++ b/src/src/readconf.c
@@ -229,9 +229,7 @@ static optionlist optionlist_config[] = {
  /* This option is now a no-op, retained for compability */
   { "drop_cr",                  opt_bool,        &drop_cr },
 /*********************************************************/
-#ifdef EXPERIMENTAL_DSN
   { "dsn_advertise_hosts",      opt_stringptr,   &dsn_advertise_hosts },
-#endif
   { "dsn_from",                 opt_stringptr,   &dsn_from },
   { "envelope_to_remove",       opt_bool,        &envelope_to_remove },
   { "errors_copy",              opt_stringptr,   &errors_copy },
diff --git a/src/src/receive.c b/src/src/receive.c
index 0466cab8d..8ab3166d0 100644
--- a/src/src/receive.c
+++ b/src/src/receive.c
@@ -497,10 +497,8 @@ recipients_list[recipients_count].bmi_optin = bmi_current_optin;
 /* reset optin string pointer for next recipient */
 bmi_current_optin = NULL;
 #endif
-#ifdef EXPERIMENTAL_DSN
 recipients_list[recipients_count].orcpt = NULL;
 recipients_list[recipients_count].dsn_flags = 0;
-#endif
 recipients_list[recipients_count++].errors_to = NULL;
 }
 
diff --git a/src/src/route.c b/src/src/route.c
index c640e9e71..09503044f 100644
--- a/src/src/route.c
+++ b/src/src/route.c
@@ -58,10 +58,8 @@ optionlist optionlist_routers[] = {
                  (void *)offsetof(router_instance, domains) },
   { "driver",             opt_stringptr|opt_public,
                  (void *)offsetof(router_instance, driver_name) },
-  #ifdef EXPERIMENTAL_DSN
   { "dsn_lasthop",        opt_bool|opt_public,
                  (void *)offsetof(router_instance, dsn_lasthop) },
-  #endif
   { "errors_to",          opt_stringptr|opt_public,
                  (void *)(offsetof(router_instance, errors_to)) },
   { "expn",               opt_bool|opt_public,
@@ -275,14 +273,12 @@ for (r = routers; r != NULL; r = r->next)
   if (r->pass_router_name != NULL)
     set_router(r, r->pass_router_name, &(r->pass_router), TRUE);
 
-  #ifdef EXPERIMENTAL_DSN
-    DEBUG(D_route) {
+  DEBUG(D_route) {
       if (r->dsn_lasthop == FALSE)
         debug_printf("DSN: %s propagating DSN\n", r->name);
       else
         debug_printf("DSN: %s lasthop set\n", r->name);
       }
-  #endif
   }
 }
 
@@ -1364,10 +1360,8 @@ new->p.errors_address = parent->p.errors_address;
 
 copyflag(new, addr, af_propagate);
 new->p.address_data = addr->p.address_data;
-#ifdef EXPERIMENTAL_DSN
 new->dsn_flags = addr->dsn_flags;
 new->dsn_orcpt = addr->dsn_orcpt;
-#endif
 
 
 /* As it has turned out, we haven't set headers_add or headers_remove for the
@@ -1675,7 +1669,6 @@ for (r = (addr->start_router == NULL)? routers : addr->start_router;
 
   /* Run the router, and handle the consequences. */
 
-#ifdef EXPERIMENTAL_DSN
 /* ... but let us check on DSN before. If this should be the last hop for DSN
    set flag
 */
@@ -1684,7 +1677,6 @@ for (r = (addr->start_router == NULL)? routers : addr->start_router;
     addr->dsn_flags |= rf_dsnlasthop;
     HDEBUG(D_route) debug_printf("DSN: last hop for %s\n", addr->address);
   }
-#endif
 
   HDEBUG(D_route) debug_printf("calling %s router\n", r->name);
 
diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c
index 54dcaa5e5..d646fe0bd 100644
--- a/src/src/smtp_in.c
+++ b/src/src/smtp_in.c
@@ -121,9 +121,7 @@ static BOOL auth_advertised;
 #ifdef SUPPORT_TLS
 static BOOL tls_advertised;
 #endif
-#ifdef EXPERIMENTAL_DSN
 static BOOL dsn_advertised;
-#endif
 static BOOL esmtp;
 static BOOL helo_required = FALSE;
 static BOOL helo_verify = FALSE;
@@ -220,9 +218,7 @@ enum {
 #ifndef DISABLE_PRDR
   ENV_MAIL_OPT_PRDR,
 #endif
-#ifdef EXPERIMENTAL_DSN
   ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
-#endif
   ENV_MAIL_OPT_NULL
   };
 typedef struct {
@@ -238,10 +234,8 @@ static env_mail_type_t env_mail_type_list[] = {
 #ifndef DISABLE_PRDR
     { US"PRDR",   ENV_MAIL_OPT_PRDR,   FALSE },
 #endif
-#ifdef EXPERIMENTAL_DSN
     { US"RET",    ENV_MAIL_OPT_RET,    TRUE },
     { US"ENVID",  ENV_MAIL_OPT_ENVID,  TRUE },
-#endif
     { US"NULL",   ENV_MAIL_OPT_NULL,   FALSE }
   };
 
@@ -1500,11 +1494,9 @@ sender_verified_list = NULL;        /* No senders verified */
 memset(sender_address_cache, 0, sizeof(sender_address_cache));
 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
 
-#ifdef EXPERIMENTAL_DSN
 /* Reset the DSN flags */
 dsn_ret = 0;
 dsn_envid = NULL;
-#endif
 
 authenticated_sender = NULL;
 #ifdef EXPERIMENTAL_BRIGHTMAIL
@@ -1855,9 +1847,7 @@ tls_in.sni = NULL;
 tls_in.ocsp = OCSP_NOT_REQ;
 tls_advertised = FALSE;
 #endif
-#ifdef EXPERIMENTAL_DSN
 dsn_advertised = FALSE;
-#endif
 
 /* Reset ACL connection variables */
 
@@ -3147,10 +3137,8 @@ while (done <= 0)
   int ptr, size, rc;
   int c, i;
   auth_instance *au;
-#ifdef EXPERIMENTAL_DSN
   uschar *orcpt = NULL;
   int flags;
-#endif
 
   switch(smtp_read_command(TRUE))
     {
@@ -3495,9 +3483,7 @@ while (done <= 0)
     #ifdef SUPPORT_TLS
     tls_advertised = FALSE;
     #endif
-    #ifdef EXPERIMENTAL_DSN
     dsn_advertised = FALSE;
-    #endif
 
     smtp_code = US"250 ";        /* Default response code plus space*/
     if (user_msg == NULL)
@@ -3581,7 +3567,6 @@ while (done <= 0)
         s = string_cat(s, &size, &ptr, US"-8BITMIME\r\n", 11);
         }
 
-      #ifdef EXPERIMENTAL_DSN
       /* Advertise DSN support if configured to do so. */
       if (verify_check_host(&dsn_advertise_hosts) != FAIL) 
         {
@@ -3589,7 +3574,6 @@ while (done <= 0)
         s = string_cat(s, &size, &ptr, US"-DSN\r\n", 6);
         dsn_advertised = TRUE;
         }
-      #endif
 
       /* Advertise ETRN if there's an ACL checking whether a host is
       permitted to issue it; a check is made when any host actually tries. */
@@ -3846,8 +3830,6 @@ while (done <= 0)
           arg_error = TRUE;
           break;
 
-        #ifdef EXPERIMENTAL_DSN
-  
         /* Handle the two DSN options, but only if configured to do so (which
         will have caused "DSN" to be given in the EHLO response). The code itself
         is included only if configured in at build time. */
@@ -3883,7 +3865,6 @@ while (done <= 0)
             DEBUG(D_receive) debug_printf("DSN_ENVID: %s\n", dsn_envid);
           }
           break;
-        #endif
 
         /* Handle the AUTH extension. If the value given is not "<>" and either
         the ACL says "yes" or there is no ACL but the sending host is
@@ -4161,8 +4142,7 @@ while (done <= 0)
       rcpt_fail_count++;
       break;
       }
-    
-    #ifdef EXPERIMENTAL_DSN
+
     /* Set the DSN flags orcpt and dsn_flags from the session*/
     orcpt = NULL;
     flags = 0;
@@ -4245,7 +4225,6 @@ while (done <= 0)
         break;
         }
       }
-    #endif
 
     /* Apply SMTP rewriting then extract the working address. Don't allow "<>"
     as a recipient address */
@@ -4360,8 +4339,7 @@ while (done <= 0)
       if (user_msg == NULL) smtp_printf("250 Accepted\r\n");
         else smtp_user_msg(US"250", user_msg);
       receive_add_recipient(recipient, -1);
-      
-      #ifdef EXPERIMENTAL_DSN
+ 
       /* Set the dsn flags in the recipients_list */
       if (orcpt != NULL)
         recipients_list[recipients_count-1].orcpt = orcpt;
@@ -4373,8 +4351,6 @@ while (done <= 0)
       else
         recipients_list[recipients_count-1].dsn_flags = 0;
       DEBUG(D_receive) debug_printf("DSN: orcpt: %s  flags: %d\n", recipients_list[recipients_count-1].orcpt, recipients_list[recipients_count-1].dsn_flags);
-      #endif
-      
       }
 
     /* The recipient was discarded */
diff --git a/src/src/spool_in.c b/src/src/spool_in.c
index bd8f094d3..79970cb40 100644
--- a/src/src/spool_in.c
+++ b/src/src/spool_in.c
@@ -299,10 +299,8 @@ tls_in.ocsp = OCSP_NOT_REQ;
 spam_score_int = NULL;
 #endif
 
-#ifdef EXPERIMENTAL_DSN
 dsn_ret = 0;
 dsn_envid = NULL;
-#endif
 
 /* Generate the full name and open the file. If message_subdir is already
 set, just look in the given directory. Otherwise, look in both the split
@@ -493,13 +491,11 @@ for (;;)
     case 'd':
     if (Ustrcmp(p, "eliver_firsttime") == 0)
       deliver_firsttime = TRUE;
-#ifdef EXPERIMENTAL_DSN
     /* Check if the dsn flags have been set in the header file */
     else if (Ustrncmp(p, "sn_ret", 6) == 0)
       dsn_ret= atoi(CS big_buffer + 8);
     else if (Ustrncmp(p, "sn_envid", 8) == 0)
       dsn_envid = string_copy(big_buffer + 11);
-#endif
     break;
 
     case 'f':
@@ -645,10 +641,8 @@ for (recipients_count = 0; recipients_count < rcount; recipients_count++)
   {
   int nn;
   int pno = -1;
-#ifdef EXPERIMENTAL_DSN
   int dsn_flags = 0;
   uschar *orcpt = NULL;
-#endif
   uschar *errors_to = NULL;
   uschar *p;
 
@@ -725,7 +719,7 @@ for (recipients_count = 0; recipients_count < rcount; recipients_count++)
     {
     int flags;
 
-#if defined(EXPERIMENTAL_DSN) && !defined (COMPILE_UTILITY)
+#if !defined (COMPILE_UTILITY)
     DEBUG(D_deliver) debug_printf("**** SPOOL_IN - Exim 4 standard format spoolfile\n");
 #endif
 
@@ -745,7 +739,6 @@ for (recipients_count = 0; recipients_count < rcount; recipients_count++)
       }
 
     *(--p) = 0;   /* Terminate address */
-#ifdef EXPERIMENTAL_DSN
     if ((flags & 0x02) != 0)      /* one_time data exists */
       {
       int len;
@@ -760,9 +753,8 @@ for (recipients_count = 0; recipients_count < rcount; recipients_count++)
       }
 
     *(--p) = 0;   /* Terminate address */
-#endif  /* EXPERIMENTAL_DSN */
     }
-#if defined(EXPERIMENTAL_DSN) && !defined(COMPILE_UTILITY)
+#if !defined(COMPILE_UTILITY)
   else
     { DEBUG(D_deliver) debug_printf("**** SPOOL_IN - No additional fields\n"); }
 
@@ -776,15 +768,13 @@ for (recipients_count = 0; recipients_count < rcount; recipients_count++)
     DEBUG(D_deliver) debug_printf("**** SPOOL_IN - address: |%s| errorsto: |%s|\n",
       big_buffer, errors_to);
     }
-#endif  /* EXPERIMENTAL_DSN */
+#endif
 
   recipients_list[recipients_count].address = string_copy(big_buffer);
   recipients_list[recipients_count].pno = pno;
   recipients_list[recipients_count].errors_to = errors_to;
-#ifdef EXPERIMENTAL_DSN
   recipients_list[recipients_count].orcpt = orcpt;
   recipients_list[recipients_count].dsn_flags = dsn_flags;
-#endif
   }
 
 /* The remainder of the spool header file contains the headers for the message,
diff --git a/src/src/spool_out.c b/src/src/spool_out.c
index 67ac8bce7..fc56057c1 100644
--- a/src/src/spool_out.c
+++ b/src/src/spool_out.c
@@ -245,13 +245,11 @@ if (tls_in.ourcert)
 if (tls_in.ocsp)	 fprintf(f, "-tls_ocsp %d\n",   tls_in.ocsp);
 #endif
 
-#ifdef EXPERIMENTAL_DSN
 /* Write the dsn flags to the spool header file */
 DEBUG(D_deliver) debug_printf("DSN: Write SPOOL :-dsn_envid %s\n", dsn_envid);
 if (dsn_envid != NULL) fprintf(f, "-dsn_envid %s\n", dsn_envid);
 DEBUG(D_deliver) debug_printf("DSN: Write SPOOL :-dsn_ret %d\n", dsn_ret);
 if (dsn_ret != 0) fprintf(f, "-dsn_ret %d\n", dsn_ret);
-#endif
 
 /* To complete the envelope, write out the tree of non-recipients, followed by
 the list of recipients. These won't be disjoint the first time, when no
@@ -263,34 +261,21 @@ fprintf(f, "%d\n", recipients_count);
 for (i = 0; i < recipients_count; i++)
   {
   recipient_item *r = recipients_list + i;
-#ifdef EXPERIMENTAL_DSN
 DEBUG(D_deliver) debug_printf("DSN: Flags :%d\n", r->dsn_flags);
-#endif
-  if (r->pno < 0 && r->errors_to == NULL
-    #ifdef EXPERIMENTAL_DSN
-     && r->dsn_flags == 0
-    #endif
-    )
+  if (r->pno < 0 && r->errors_to == NULL && r->dsn_flags == 0)
     fprintf(f, "%s\n", r->address);
   else
     {
     uschar *errors_to = (r->errors_to == NULL)? US"" : r->errors_to;
-    #ifdef EXPERIMENTAL_DSN
     /* for DSN SUPPORT extend exim 4 spool in a compatible way by
        adding new values upfront and add flag 0x02 */
     uschar *orcpt = (r->orcpt == NULL)? US"" : r->orcpt;
     fprintf(f, "%s %s %d,%d %s %d,%d#3\n", r->address, orcpt, Ustrlen(orcpt), r->dsn_flags,
       errors_to, Ustrlen(errors_to), r->pno);
-    #else
-    fprintf(f, "%s %s %d,%d#1\n", r->address, errors_to,
-      Ustrlen(errors_to), r->pno);
-    #endif
     }
     
-    #ifdef EXPERIMENTAL_DSN
       DEBUG(D_deliver) debug_printf("DSN: **** SPOOL_OUT - address: |%s| errorsto: |%s| orcpt: |%s| dsn_flags: %d\n",
          r->address, r->errors_to, r->orcpt, r->dsn_flags);
-    #endif
   }
 
 /* Put a blank line before the headers */
diff --git a/src/src/structs.h b/src/src/structs.h
index 2250bbbde..3cdf12a8f 100644
--- a/src/src/structs.h
+++ b/src/src/structs.h
@@ -286,9 +286,7 @@ typedef struct router_instance {
   BOOL    verify_sender;          /* Use this router when verifying a sender */
   BOOL    uid_set;                /* Flag to indicate uid is set */
   BOOL    unseen;                 /* If TRUE carry on, even after success */
-#ifdef EXPERIMENTAL_DSN
   BOOL    dsn_lasthop;            /* If TRUE, this router is a DSN endpoint */
-#endif
 
   int     self_code;              /* Encoded version of "self" */
   uid_t   uid;                    /* Fixed uid value */
@@ -560,11 +558,9 @@ typedef struct address_item {
   uschar *auth_id;		  /* auth "login" name used by transport */
   uschar *auth_sndr;		  /* AUTH arg to SMTP MAIL, used by transport */
 
-  #ifdef EXPERIMENTAL_DSN
   uschar *dsn_orcpt;              /* DSN orcpt value */
   int     dsn_flags;              /* DSN flags */
   int     dsn_aware;              /* DSN aware flag */
-  #endif
 
   uid_t   uid;                    /* uid for transporting */
   gid_t   gid;                    /* gid for transporting */
diff --git a/src/src/transport.c b/src/src/transport.c
index 30e4268d1..58fc4ec93 100644
--- a/src/src/transport.c
+++ b/src/src/transport.c
@@ -1842,10 +1842,8 @@ if ((pid = fork()) == 0)
 
   argv = child_exec_exim(CEE_RETURN_ARGV, TRUE, &i, FALSE, 0);
 
-  #ifdef EXPERIMENTAL_DSN
   /* Call with the dsn flag */
   if (smtp_use_dsn) argv[i++] = US"-MCD";
-  #endif
 
   if (smtp_authenticated) argv[i++] = US"-MCA";
 
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index 181081b60..017cc5a37 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -273,14 +273,12 @@ smtp_transport_options_block smtp_transport_option_defaults = {
 #endif
 };
 
-#ifdef EXPERIMENTAL_DSN
 /* some DSN flags for use later */
 
 static int     rf_list[] = {rf_notify_never, rf_notify_success,
                             rf_notify_failure, rf_notify_delay };
 
 static uschar *rf_names[] = { US"NEVER", US"SUCCESS", US"FAILURE", US"DELAY" };
-#endif
 
 
 
@@ -1278,9 +1276,7 @@ BOOL pass_message = FALSE;
 BOOL prdr_offered = FALSE;
 BOOL prdr_active;
 #endif
-#ifdef EXPERIMENTAL_DSN
 BOOL dsn_all_lasthop = TRUE;
-#endif
 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
 BOOL dane = FALSE;
 dns_answer tlsa_dnsa;
@@ -1743,12 +1739,10 @@ if (continue_hostname == NULL
     {DEBUG(D_transport) debug_printf("PRDR usable\n");}
 #endif
 
-#ifdef EXPERIMENTAL_DSN
   /* Note if the server supports DSN */
   smtp_use_dsn = esmtp && pcre_exec(regex_DSN, NULL, CS buffer, (int)Ustrlen(CS buffer), 0,
        PCRE_EOPT, NULL, 0) >= 0;
   DEBUG(D_transport) debug_printf("use_dsn=%d\n", smtp_use_dsn);
-#endif
 
   /* Note if the response to EHLO specifies support for the AUTH extension.
   If it has, check that this host is one we want to authenticate to, and do
@@ -1846,7 +1840,6 @@ if (prdr_offered)
   }
 #endif
 
-#ifdef EXPERIMENTAL_DSN
 /* check if all addresses have lasthop flag */
 /* do not send RET and ENVID if true */
 dsn_all_lasthop = TRUE;
@@ -1876,7 +1869,6 @@ if ((smtp_use_dsn) && (dsn_all_lasthop == FALSE))
     while (*p) p++;
     }
   }
-#endif
 
 /* If an authenticated_sender override has been specified for this transport
 instance, expand it. If the expansion is forced to fail, and there was already
@@ -1943,16 +1935,13 @@ for (addr = first_addr;
   int count;
   BOOL no_flush;
 
-#ifdef EXPERIMENTAL_DSN
   addr->dsn_aware = smtp_use_dsn ? dsn_support_yes : dsn_support_no;
-#endif
 
   if (addr->transport_return != PENDING_DEFER) continue;
 
   address_count++;
   no_flush = smtp_use_pipelining && (!mua_wrapper || addr->next != NULL);
 
-#ifdef EXPERIMENTAL_DSN
   /* Add any DSN flags to the rcpt command and add to the sent string */
 
   p = buffer;
@@ -1983,21 +1972,14 @@ for (addr = first_addr;
       while (*p) p++;
       }
     }
-#endif
-
 
   /* Now send the RCPT command, and process outstanding responses when
   necessary. After a timeout on RCPT, we just end the function, leaving the
   yield as OK, because this error can often mean that there is a problem with
   just one address, so we don't want to delay the host. */
 
-#ifdef EXPERIMENTAL_DSN
   count = smtp_write_command(&outblock, no_flush, "RCPT TO:<%s>%s%s\r\n",
     transport_rcpt_address(addr, tblock->rcpt_include_affixes), igquotstr, buffer);
-#else
-  count = smtp_write_command(&outblock, no_flush, "RCPT TO:<%s>%s\r\n",
-    transport_rcpt_address(addr, tblock->rcpt_include_affixes), igquotstr);
-#endif
 
   if (count < 0) goto SEND_FAILED;
   if (count > 0)