diff -urN ../exim-4.94.orig/src/globals.c ./src/globals.c
--- ../exim-4.94.orig/src/globals.c	2020-05-30 23:35:38.000000000 +0300
+++ ./src/globals.c	2020-06-07 11:24:05.384459000 +0300
@@ -1439,7 +1439,8 @@
 int     smtp_accept_max        = 20;
 int     smtp_accept_max_nonmail= 10;
 uschar *smtp_accept_max_nonmail_hosts = US"*";
-int     smtp_accept_max_per_connection = 1000;
+//int     smtp_accept_max_per_connection = 1000;
+uschar *smtp_accept_max_per_connection = NULL;
 uschar *smtp_accept_max_per_host = NULL;
 int     smtp_accept_queue      = 0;
 int     smtp_accept_queue_per_connection = 10;
diff -urN ../exim-4.94.orig/src/globals.h ./src/globals.h
--- ../exim-4.94.orig/src/globals.h	2020-05-30 23:35:38.000000000 +0300
+++ ./src/globals.h	2020-06-07 11:19:06.541905000 +0300
@@ -919,7 +919,8 @@
 extern int     smtp_accept_max;        /* Max SMTP connections */
 extern int     smtp_accept_max_nonmail;/* Max non-mail commands in one con */
 extern uschar *smtp_accept_max_nonmail_hosts; /* Limit non-mail cmds from these hosts */
-extern int     smtp_accept_max_per_connection; /* Max msgs per connection */
+//extern int     smtp_accept_max_per_connection; /* Max msgs per connection */
+extern uschar *smtp_accept_max_per_connection; /* Max msgs per connection */
 extern uschar *smtp_accept_max_per_host; /* Max SMTP cons from one IP addr */
 extern int     smtp_accept_queue;      /* Queue after so many connections */
 extern int     smtp_accept_queue_per_connection; /* Queue after so many msgs */
diff -urN ../exim-4.94.orig/src/readconf.c ./src/readconf.c
--- ../exim-4.94.orig/src/readconf.c	2020-05-30 23:35:38.000000000 +0300
+++ ./src/readconf.c	2020-07-05 16:32:43.461805000 +0300
@@ -297,7 +297,7 @@
   { "smtp_accept_max",          opt_int,         {&smtp_accept_max} },
   { "smtp_accept_max_nonmail",  opt_int,         {&smtp_accept_max_nonmail} },
   { "smtp_accept_max_nonmail_hosts", opt_stringptr, {&smtp_accept_max_nonmail_hosts} },
-  { "smtp_accept_max_per_connection", opt_int,   {&smtp_accept_max_per_connection} },
+  { "smtp_accept_max_per_connection", opt_stringptr, {&smtp_accept_max_per_connection} },
   { "smtp_accept_max_per_host", opt_stringptr,   {&smtp_accept_max_per_host} },
   { "smtp_accept_queue",        opt_int,         {&smtp_accept_queue} },
   { "smtp_accept_queue_per_connection", opt_int, {&smtp_accept_queue_per_connection} },
diff -urN ../exim-4.94.orig/src/smtp_in.c ./src/smtp_in.c
--- ../exim-4.94.orig/src/smtp_in.c	2020-05-30 23:35:38.000000000 +0300
+++ ./src/smtp_in.c	2020-06-07 11:22:56.776883000 +0300
@@ -4580,8 +4580,40 @@
       /* Check to see if the limit for messages per connection would be
       exceeded by accepting further messages. */
 
-      if (smtp_accept_max_per_connection > 0 &&
-	  smtp_mailcmd_count > smtp_accept_max_per_connection)
+
+#define DEFAULT_ACCEPT_MAX_PER_CONNECTION 1000
+int accept_max_per_connection = -1;
+if (smtp_accept_max_per_connection != NULL)
+  {
+  uschar *expanded = expand_string(smtp_accept_max_per_connection);
+  if (expanded == NULL)
+    {
+    if (!f.expand_string_forcedfail)
+      log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_connection "
+        "failed for message from %s: %s; fallback to default value %d", host_and_ident(FALSE), expand_string_message, DEFAULT_ACCEPT_MAX_PER_CONNECTION);
+    }
+  /* For speed, interpret a decimal number inline here */
+  else
+    {
+    accept_max_per_connection = 0;
+    uschar *s = expanded;
+    while (isdigit(*s))
+      accept_max_per_connection = accept_max_per_connection * 10 + *s++ - '0';
+    if (*s != 0)
+      {
+        log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_connection "
+          "for message from %s contains non-digit: %s; fallback to default value %d", host_and_ident(FALSE), expanded, DEFAULT_ACCEPT_MAX_PER_CONNECTION);
+        accept_max_per_connection = DEFAULT_ACCEPT_MAX_PER_CONNECTION;
+      }
+    }
+  }
+if (accept_max_per_connection == -1) accept_max_per_connection = DEFAULT_ACCEPT_MAX_PER_CONNECTION;
+
+
+//      if (smtp_accept_max_per_connection > 0 &&
+//	  smtp_mailcmd_count > smtp_accept_max_per_connection)
+      if (accept_max_per_connection > 0 &&
+	  smtp_mailcmd_count > accept_max_per_connection)
 	{
 	smtp_printf("421 too many messages in this connection\r\n", FALSE);
 	log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "