my ($validate, $confirm);
 my (@suppress_cc);
 
+my $not_set_by_user = "true but not set by the user";
+
 my %config_bool_settings = (
     "thread" => [\$thread, 1],
-    "chainreplyto" => [\$chain_reply_to, 1],
+    "chainreplyto" => [\$chain_reply_to, $not_set_by_user],
     "suppressfrom" => [\$suppress_from, undef],
     "signedoffbycc" => [\$signed_off_by_cc, undef],
     "signedoffcc" => [\$signed_off_by_cc, undef],      # Deprecated
     "from" => \$sender,
 );
 
+# Help users prepare for 1.7.0
+sub chain_reply_to {
+       if (defined $chain_reply_to &&
+           $chain_reply_to eq $not_set_by_user) {
+               print STDERR
+                   "In git 1.7.0, the default will be changed to --no-chain-reply-to\n" .
+                   "Set sendemail.chainreplyto configuration variable to true if\n" .
+                   "you want to keep --chain-reply-to as your default.\n";
+               $chain_reply_to = 1;
+       }
+       return $chain_reply_to;
+}
+
 # Handle Uncouth Termination
 sub signal_handler {
 
 
        my @sendmail_parameters = ('-i', @recipients);
        my $raw_from = $sanitized_sender;
-       $raw_from = $envelope_sender if (defined $envelope_sender);
+       if (defined $envelope_sender && $envelope_sender ne "auto") {
+               $raw_from = $envelope_sender;
+       }
        $raw_from = extract_valid_address($raw_from);
        unshift (@sendmail_parameters,
                        '-f', $raw_from) if(defined $envelope_sender);
 
        # set up for the next message
        if ($thread && $message_was_sent &&
-               ($chain_reply_to || !defined $reply_to || length($reply_to) == 0)) {
+               (chain_reply_to() || !defined $reply_to || length($reply_to) == 0)) {
                $reply_to = $message_id;
                if (length $references > 0) {
                        $references .= "\n $message_id";