--- a/src/deliver.c
+++ b/src/deliver.c
@@ -5696,7 +5696,7 @@
 
   /* output human readable part as text/plain section */
   fprintf(fp, "--%s\n"
-      "Content-type: text/plain; charset=us-ascii\n\n",
+      "Content-type: text/plain; charset=utf-8\n\n",
     bound);
 
   if ((emf_text = next_emf(emf, US"intro")))
@@ -6066,7 +6066,7 @@
 
 /* output human readable part as text/plain section */
 fprintf(f, "--%s\n"
-    "Content-type: text/plain; charset=us-ascii\n\n",
+    "Content-type: text/plain; charset=utf-8\n\n",
   bound);
 
 if ((wmf_text = next_emf(wmf, US"intro")))
@@ -6281,7 +6281,7 @@
 	"MIME-Version: 1.0\n\n"
 
 	"--%s\n"
-	"Content-type: text/plain; charset=us-ascii\n\n"
+	"Content-type: text/plain; charset=utf-8\n\n"
 
 	"This message was created automatically by mail delivery software.\n"
 	" ----- The following addresses had successful delivery notifications -----\n",
