--- mblaze-1.1/mmime.c	2021-01-14 10:45:22.000000000 -0500
+++ mblaze-1.1f/mmime.c	2021-06-12 20:35:09.994308179 -0400
@@ -134,6 +134,68 @@
 	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)
 {
@@ -401,8 +463,8 @@
 				inheader = 0;
 				printf("MIME-Version: 1.0\n");
 				if (rflag) {
-					printf("Content-Type: text/plain; charset=UTF-8\n");
-					printf("Content-Transfer-Encoding: quoted-printable\n\n");
+					printf("Content-Type: text/plain; charset=US-ASCII; format=flowed\n");
+					printf("Content-Transfer-Encoding: 7bit\n\n");
 
 				} else {
 					printf("Content-Type: %s; boundary=\"%s\"\n", tflag, sep);
@@ -435,14 +497,14 @@
 
 		if (!rflag && !intext) {
 			printf("\n--%s\n", sep);
-			printf("Content-Type: text/plain; charset=UTF-8\n");
+			printf("Content-Type: text/plain; charset=US-ASCII; format=flowed\n");
 			printf("Content-Disposition: inline\n");
-			printf("Content-Transfer-Encoding: quoted-printable\n\n");
+			printf("Content-Transfer-Encoding: 7bit\n\n");
 
 			intext = 1;
 		}
 
-		gen_qp((uint8_t *)line, strlen(line), 78, 0);
+		gen_flowd((uint8_t *)line, strlen(line), 78, 0);
 	}
 	if (!rflag && !inheader)
 		printf("\n--%s--\n", sep);
 			printf 'Bcc: \n'