--- mblaze-1.2/mmime.c	2021-12-12 11:39:30.000000000 -0500
+++ mblaze-1.2f/mmime.c	2022-05-12 09:13:44.371637134 -0400
@@ -143,6 +143,70 @@ gen_qp(uint8_t *s, off_t size, size_t ma
 	return linelen;
 }
 
+
+size_t
+gen_flowd(uint8_t *s, off_t size, size_t maxlinelen, size_t linelen)
+{
+       off_t i;
+       int header = linelen > 0;
+
+       for (i = 0; i < size; i++) {
+               // inspect utf8 sequence to not wrap in between multibyte
+               int mb;
+               if      ((s[i] & 0x80) == 0)    mb = 3;
+               else if ((s[i] & 0xc0) == 0x80) mb = 3;
+               else if ((s[i] & 0xe0) == 0xc0) mb = 6;
+               else if ((s[i] & 0xf0) == 0xe0) mb = 9;
+               else if ((s[i] & 0xf8) == 0xf0) mb = 12;
+               else mb = 3;
+
+               if (linelen >= maxlinelen-mb-!!header) {
+                       linelen = 0;
+                       if (header) {
+                               printf("\n");
+                       } else {
+                               puts(" ");
+                       }
+               }
+
+
+               if ((s[i] > 126) ||
+                   (linelen == 0 &&
+                    (strncmp((char *)s, "From ", 5) == 0 ||
+                    (s[i] == '.' && i+1 < size &&
+                     (s[i+1] == '\n' || s[i+1] == '\r'))))) {
+                       putc_unlocked(s[i], stdout);
+                       linelen ++;
+               } else if (header &&
+                          (s[i] == '\n' || s[i] == '\t' || s[i] == '_')) {
+                       putc_unlocked(s[i], stdout);
+                       linelen ++;
+               } else if (header && s[i] == ' ') {
+                       putc_unlocked('_', stdout);
+                       linelen++;
+               } else if (s[i] < 33 && s[i] != '\n') {
+                       if ((s[i] == ' ' || s[i] == '\t') &&
+                           i+1 < size &&
+                           (s[i+1] != '\n' && s[i+1] != '\r')) {
+                               putc_unlocked(s[i], stdout);
+                               linelen++;
+                       } else {
+                               putc_unlocked(s[i], stdout);
+                               linelen++;
+                       }
+               } else if (s[i] == '\n') {
+                       putc_unlocked('\n', stdout);
+                       linelen = 0;
+               } else {
+                       putc_unlocked(s[i], stdout);
+                       linelen++;
+               }
+       }
+       if (linelen > 0 && !header)
+               puts("\n");
+       return linelen;
+}
+
 static const char *
 basenam(const char *s)
 {
@@ -444,8 +508,8 @@ gen_build()
 				inheader = 0;
 				printf("MIME-Version: 1.0\n");
 				if (rflag) {
-					printf("Content-Type:%s", contenttype ? contenttype : " text/plain; charset=UTF-8\n");
-					printf("Content-Transfer-Encoding:%s", contenttransferenc ? contenttransferenc : " quoted-printable\n");
+					printf("Content-Type:%s", contenttype ? contenttype : " text/plain; charset=US-ASCII; format=flowed\n");
+					printf("Content-Transfer-Encoding:%s", contenttransferenc ? contenttransferenc : " 7bit\n");
 					printf("\n");
 				} else {
 					printf("Content-Type: %s; boundary=\"%s\"\n", tflag, sep);
@@ -487,9 +551,9 @@ gen_build()
 
 		if (!rflag && !intext) {
 			printf("\n--%s\n", sep);
-			printf("Content-Type:%s", contenttype ? contenttype : " text/plain; charset=UTF-8\n");
+			printf("Content-Type:%s", contenttype ? contenttype : " text/plain; charset=US-ASCII; format=flowed\n");
 			printf("Content-Disposition: inline\n");
-			printf("Content-Transfer-Encoding:%s", contenttransferenc ? contenttransferenc : " quoted-printable\n");
+			printf("Content-Transfer-Encoding:%s", contenttransferenc ? contenttransferenc : " 7bit\n");
 			printf("\n");
 
 			intext = 1;
@@ -498,7 +562,7 @@ gen_build()
 		if (contenttransferenc)
 			printf("%s", line);
 		else
-			gen_qp((uint8_t *)line, strlen(line), 78, 0);
+			gen_flowd((uint8_t *)line, strlen(line), 78, 0);
 
 		emptybody = 0;
 	}