--- init.h.orig	2017-04-12 23:01:17 UTC
+++ init.h
@@ -871,6 +871,11 @@ struct option_t MuttVars[] = {
   ** sent to both the list and your address, resulting in two copies
   ** of the same email for you.
   */
+  { "force_base64",   DT_BOOL, R_NONE, OPTFORCEBASE64, 0 },
+  /*
+  ** .pp
+  ** If you need to encode all text parts to base64, set this option.
+  */
   { "force_name",	DT_BOOL, R_NONE, OPTFORCENAME, 0 },
   /*
   ** .pp
--- mutt.h.orig	2017-04-12 23:01:17 UTC
+++ mutt.h
@@ -355,6 +355,7 @@ enum
   OPTFCCCLEAR,
   OPTFLAGSAFE,
   OPTFOLLOWUPTO,
+  OPTFORCEBASE64,
   OPTFORCENAME,
   OPTFORWDECODE,
   OPTFORWQUOTE,
--- sendlib.c.orig	2017-04-12 23:01:08 UTC
+++ sendlib.c
@@ -1171,7 +1171,9 @@ static void mutt_set_encoding (BODY *b, 
   if (b->type == TYPETEXT)
   {
     char *chsname = mutt_get_body_charset (send_charset, sizeof (send_charset), b);
-    if ((info->lobin && ascii_strncasecmp (chsname, "iso-2022", 8)) || info->linemax > 990 || (info->from && option (OPTENCODEFROM)))
+    if (option (OPTFORCEBASE64))
+      b->encoding = ENCBASE64;
+    else if ((info->lobin && ascii_strncasecmp (chsname, "iso-2022", 8)) || info->linemax > 990 || (info->from && option (OPTENCODEFROM)))
       b->encoding = ENCQUOTEDPRINTABLE;
     else if (info->hibin)
       b->encoding = option (OPTALLOW8BIT) ? ENC8BIT : ENCQUOTEDPRINTABLE;