- if ($ct =~ m!\btext/plain\b!i || $ct =~ m!\bmultipart/mixed\b!i) {
- # Try to assume UTF-8 because Alpine seems to
- # do wacky things and set charset=X-UNKNOWN
- $part->charset_set('UTF-8');
- $s = eval { $part->body_str };
+ if ($err && ($ct =~ m!\btext/\b!i ||
+ $ct =~ m!\bmultipart/mixed\b!i)) {
+ my $cte = $part->header_raw('Content-Transfer-Encoding');
+ if (defined($cte) && $cte =~ /\b7bit\b/i) {
+ $s = $part->body;
+ $err = undef if $s =~ /\A[[:ascii:]]+\z/s;
+ } else {
+ # Try to assume UTF-8 because Alpine seems to
+ # do wacky things and set charset=X-UNKNOWN
+ $part->charset_set('UTF-8');
+ $s = eval { $part->body_str };
+ }