diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5ca2bf23c..9707e9d0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
 - Add option to purge deleted mails older than 30, 60 or 90 days (#5493)
 - Add ability to mark multiple messages as not deleted at once (#5133)
 - Add possibility to disable line-wrapping of sent mail body (#5101)
+- Improve auto-wrapping of plain text messages on preview and reply, don't wrap non-format=flowed content (#6974)
 - Support displaying RTF content (including encapsulated HTML) from a TNEF attachment
 - Newmail_notifier: Improved the notification sound (#8155)
 - Add option to control links handling behavior on html to text conversion (#6485)
diff --git a/program/actions/mail/compose.php b/program/actions/mail/compose.php
index c4b55c4db..bea3ef6fb 100644
--- a/program/actions/mail/compose.php
+++ b/program/actions/mail/compose.php
@@ -828,9 +828,10 @@ class rcmail_action_mail_compose extends rcmail_action_mail_index
         }
 
         if (!$bodyIsHtml) {
-            // soft-wrap and quote message text
-            $line_length = $rcmail->config->get('line_length', 72);
-            $body = self::wrap_and_quote($body, $line_length, $reply_indent);
+            // quote the message text
+            if ($reply_indent) {
+                $body = self::quote_text($body);
+            }
 
             if ($reply_mode > 0) { // top-posting
                 $prefix = "\n\n\n" . $prefix;
@@ -1715,54 +1716,20 @@ class rcmail_action_mail_compose extends rcmail_action_mail_index
     }
 
     /**
-     * Wrap text to a given number of characters per line
-     * but respect the mail quotation of replies messages (>).
-     * Finally add another quotation level by prepending the lines
-     * with >
+     * Add quotation (>) to a replied message text.
      *
-     * @param string $text   Text to wrap
-     * @param int    $length The line width
-     * @param bool   $quote  Enable quote indentation
+     * @param string $text Text to quote
      *
-     * @return string The wrapped text
+     * @return string The quoted text
      */
-    public static function wrap_and_quote($text, $length = 72, $quote = true)
+    public static function quote_text($text)
     {
-        // Rebuild the message body with a maximum of $max chars, while keeping quoted message.
-        $max   = max(75, $length + 8);
         $lines = preg_split('/\r?\n/', trim($text));
         $out   = '';
 
         foreach ($lines as $line) {
-            // don't wrap already quoted lines
-            if (isset($line[0]) && $line[0] == '>') {
-                $line = rtrim($line);
-                if ($quote) {
-                    $line = '>' . $line;
-                }
-            }
-            // wrap lines above the length limit, but skip these
-            // special lines with links list created by rcube_html2text
-            else if (mb_strlen($line) > $max && !preg_match('|^\[[0-9]+\] https?://\S+$|', $line)) {
-                $newline = '';
-
-                foreach (explode("\n", rcube_mime::wordwrap($line, $length - 2)) as $l) {
-                    if ($quote) {
-                        $newline .= strlen($l) ? "> $l\n" : ">\n";
-                    }
-                    else {
-                        $newline .= "$l\n";
-                    }
-                }
-
-                $line = rtrim($newline);
-            }
-            else if ($quote) {
-                $line = '> ' . $line;
-            }
-
-            // Append the line
-            $out .= $line . "\n";
+            $quoted = isset($line[0]) && $line[0] == '>';
+            $out .= '>' . ($quoted ? '' : ' ') . $line . "\n";
         }
 
         return rtrim($out, "\n");
diff --git a/program/actions/mail/index.php b/program/actions/mail/index.php
index 805cc56a2..02392e7c6 100644
--- a/program/actions/mail/index.php
+++ b/program/actions/mail/index.php
@@ -1066,7 +1066,7 @@ class rcmail_action_mail_index extends rcmail_action
     {
         $options = [
             'flowed'   => $flowed,
-            'wrap'     => !$flowed,
+            'wrap'     => $flowed,
             'replacer' => 'rcmail_string_replacer',
             'delsp'    => $delsp
         ];
@@ -1694,12 +1694,4 @@ class rcmail_action_mail_index extends rcmail_action
 
         return array_values($mimetypes);
     }
-
-    /**
-     * @deprecated Moved to rcmail_action_mail_compose
-     */
-    public static function wrap_and_quote($text, $length = 72, $quote = true)
-    {
-        return rcmail_action_mail_compose::wrap_and_quote($text, $length, $quote);
-    }
 }
diff --git a/program/lib/Roundcube/rcube_text2html.php b/program/lib/Roundcube/rcube_text2html.php
index 2222b1b6b..7d751b6f1 100644
--- a/program/lib/Roundcube/rcube_text2html.php
+++ b/program/lib/Roundcube/rcube_text2html.php
@@ -145,9 +145,8 @@ class rcube_text2html
         $replacer = new $this->config['replacer']($attribs);
 
         if ($this->config['flowed']) {
-            $flowed_char = 0x01;
-            $delsp       = $this->config['delsp'];
-            $text        = rcube_mime::unfold_flowed($text, chr($flowed_char), $delsp);
+            $delsp = $this->config['delsp'];
+            $text  = rcube_mime::unfold_flowed($text, null, $delsp);
         }
 
         // search for patterns like links and e-mail addresses and replace with tokens
@@ -163,19 +162,12 @@ class rcube_text2html
 
         // wrap quoted lines with <blockquote>
         for ($n = 0, $cnt = count($text); $n < $cnt; $n++) {
-            $flowed = false;
             $first  = $text[$n][0] ?? '';
 
-            if (isset($flowed_char) && ord($first) == $flowed_char) {
-                $flowed   = true;
-                $text[$n] = substr($text[$n], 1);
-                $first    = $text[$n][0] ?? '';
-            }
-
             if ($first == '>' && preg_match('/^(>+ {0,1})+/', $text[$n], $regs)) {
                 $q        = substr_count($regs[0], '>');
                 $text[$n] = substr($text[$n], strlen($regs[0]));
-                $text[$n] = $this->_convert_line($text[$n], $flowed || $this->config['wrap']);
+                $text[$n] = $this->_convert_line($text[$n]);
                 $_length  = strlen(str_replace(' ', '', $text[$n]));
 
                 if ($q > $quote_level) {
@@ -207,7 +199,7 @@ class rcube_text2html
                 }
             }
             else {
-                $text[$n] = $this->_convert_line($text[$n], $flowed || $this->config['wrap']);
+                $text[$n] = $this->_convert_line($text[$n]);
                 $q        = 0;
                 $_length  = strlen(str_replace(' ', '', $text[$n]));
 
@@ -264,12 +256,11 @@ class rcube_text2html
     /**
      * Converts spaces in line of text
      *
-     * @param string $text      Plain text
-     * @param bool   $is_flowed Is the $text format=flowed?
+     * @param string $text Plain text
      *
      * @return string Converted text
      */
-    protected function _convert_line($text, $is_flowed)
+    protected function _convert_line($text)
     {
         static $table;
 
@@ -290,17 +281,20 @@ class rcube_text2html
         // replace HTML special and whitespace characters
         $text = strtr($text, $table);
 
-        $nbsp = $this->config['space'];
+        $nbsp      = $this->config['space'];
+        $wrappable = $this->config['flowed'] || $this->config['wrap'];
 
-        // replace spaces with non-breaking spaces
-        if ($is_flowed) {
+        // make the line wrappable
+        if ($wrappable) {
             $pos  = 0;
             $diff = 0;
+            $last = -2;
             $len  = strlen($nbsp);
             $copy = $text;
 
             while (($pos = strpos($text, ' ', $pos)) !== false) {
-                if ($pos == 0 || $text[$pos-1] == ' ') {
+                if (($pos == 0 || $text[$pos-1] == ' ') && $pos - 1 != $last) {
+                    $last = $pos;
                     $copy = substr_replace($copy, $nbsp, $pos + $diff, 1);
                     $diff += $len - 1;
                 }
diff --git a/tests/Actions/Mail/Compose.php b/tests/Actions/Mail/Compose.php
index bf500578f..c66f64de2 100644
--- a/tests/Actions/Mail/Compose.php
+++ b/tests/Actions/Mail/Compose.php
@@ -18,21 +18,20 @@ class Actions_Mail_Compose extends ActionTestCase
     }
 
     /**
-     * Test wrap_and_quote() method
+     * Test quote_text() method
      */
-    function test_wrap_and_quote()
+    function test_quote_text()
     {
         $action = new rcmail_action_mail_compose;
 
-        $this->assertSame('> ', $action->wrap_and_quote(''));
-        $this->assertSame('', $action->wrap_and_quote('', 72, false));
+        $this->assertSame('> ', $action->quote_text(''));
 
-        $result = $action->wrap_and_quote("test1\ntest2");
+        $result = $action->quote_text("test1\ntest2");
         $expected = "> test1\n> test2";
 
         $this->assertSame($expected, $result);
 
-        $result = $action->wrap_and_quote("> test1\n> test2");
+        $result = $action->quote_text("> test1\n> test2");
         $expected = ">> test1\n>> test2";
 
         $this->assertSame($expected, $result);
diff --git a/tests/Framework/Rcube.php b/tests/Framework/Rcube.php
index 1d2887ebd..f8f9dc3f5 100644
--- a/tests/Framework/Rcube.php
+++ b/tests/Framework/Rcube.php
@@ -56,5 +56,8 @@ class Framework_Rcube extends PHPUnit\Framework\TestCase
         $result = $rcube->decrypt($rcube->encrypt('test'));
 
         $this->assertSame('test', $result);
+
+        // Back to the default
+        $rcube->config->set('cipher_method', 'DES-EDE3-CBC');
     }
 }
diff --git a/tests/Framework/Text2Html.php b/tests/Framework/Text2Html.php
index 9d5280060..619e7d03a 100644
--- a/tests/Framework/Text2Html.php
+++ b/tests/Framework/Text2Html.php
@@ -51,46 +51,46 @@ class Framework_Text2Html extends PHPUnit\Framework\TestCase
         $options['flowed'] = true;
 
         $data[] = [" aaaa", "aaaa", $options];
-        $data[] = ["aaaa aaaa", ">aaaa_aaaa<", $options];
-        $data[] = ["aaaa  aaaa", ">aaaa__aaaa<", $options];
-        $data[] = ["aaaa   aaaa", ">aaaa___aaaa<", $options];
-        $data[] = ["aaaa\taaaa", ">aaaa____aaaa<", $options];
+        $data[] = ["aaaa aaaa", "aaaa aaaa", $options];
+        $data[] = ["aaaa  aaaa", "aaaa _aaaa", $options];
+        $data[] = ["aaaa   aaaa", "aaaa _ aaaa", $options];
+        $data[] = ["aaaa\taaaa", "aaaa _ _aaaa", $options];
         $data[] = ["aaaa\naaaa", "aaaa<br>aaaa", $options];
         $data[] = ["aaaa\n aaaa", "aaaa<br>aaaa", $options];
-        $data[] = ["aaaa\n  aaaa", "aaaa<br>>_aaaa<", $options];
-        $data[] = ["aaaa\n   aaaa", "aaaa<br>>__aaaa<", $options];
-        $data[] = ["\taaaa", ">____aaaa<", $options];
+        $data[] = ["aaaa\n  aaaa", "aaaa<br>_aaaa", $options];
+        $data[] = ["aaaa\n   aaaa", "aaaa<br>_ aaaa", $options];
+        $data[] = ["\taaaa", "_ _ aaaa", $options];
         $data[] = ["\naaaa", "<br>aaaa", $options];
         $data[] = ["\n aaaa", "<br>aaaa", $options];
-        $data[] = ["\n  aaaa", "<br>>_aaaa<", $options];
-        $data[] = ["\n   aaaa", "<br>>__aaaa<", $options];
+        $data[] = ["\n  aaaa", "<br>_aaaa", $options];
+        $data[] = ["\n   aaaa", "<br>_ aaaa", $options];
         $data[] = ["aaaa\n\nbbbb", "aaaa<br><br>bbbb", $options];
         $data[] = [">aaaa \n>aaaa", "<blockquote>aaaa aaaa</blockquote>", $options];
         $data[] = [">aaaa\n>aaaa", "<blockquote>aaaa<br>aaaa</blockquote>", $options];
-        $data[] = [">aaaa \n>bbbb\ncccc dddd", "<blockquote>aaaa bbbb</blockquote>>cccc_dddd<", $options];
-        $data[] = ["\x02\x03", ">\x02\x03<", $options];
+        $data[] = [">aaaa \n>bbbb\ncccc dddd", "<blockquote>aaaa bbbb</blockquote>cccc dddd", $options];
+        $data[] = ["\x02\x03", "\x02\x03", $options];
 
         $options['flowed'] = true;
         $options['delsp']  = true;
 
         $data[] = [" aaaa", "aaaa", $options];
-        $data[] = ["aaaa aaaa", ">aaaa_aaaa<", $options];
-        $data[] = ["aaaa  aaaa", ">aaaa__aaaa<", $options];
-        $data[] = ["aaaa   aaaa", ">aaaa___aaaa<", $options];
-        $data[] = ["aaaa\taaaa", ">aaaa____aaaa<", $options];
+        $data[] = ["aaaa aaaa", "aaaa aaaa", $options];
+        $data[] = ["aaaa  aaaa", "aaaa _aaaa", $options];
+        $data[] = ["aaaa   aaaa", "aaaa _ aaaa", $options];
+        $data[] = ["aaaa\taaaa", "aaaa _ _aaaa", $options];
         $data[] = ["aaaa\naaaa", "aaaa<br>aaaa", $options];
         $data[] = ["aaaa\n aaaa", "aaaa<br>aaaa", $options];
-        $data[] = ["aaaa\n  aaaa", "aaaa<br>>_aaaa<", $options];
-        $data[] = ["aaaa\n   aaaa", "aaaa<br>>__aaaa<", $options];
-        $data[] = ["\taaaa", ">____aaaa<", $options];
+        $data[] = ["aaaa\n  aaaa", "aaaa<br>_aaaa", $options];
+        $data[] = ["aaaa\n   aaaa", "aaaa<br>_ aaaa", $options];
+        $data[] = ["\taaaa", "_ _ aaaa", $options];
         $data[] = ["\naaaa", "<br>aaaa", $options];
         $data[] = ["\n aaaa", "<br>aaaa", $options];
-        $data[] = ["\n  aaaa", "<br>>_aaaa<", $options];
-        $data[] = ["\n   aaaa", "<br>>__aaaa<", $options];
+        $data[] = ["\n  aaaa", "<br>_aaaa", $options];
+        $data[] = ["\n   aaaa", "<br>_ aaaa", $options];
         $data[] = ["aaaa\n\nbbbb", "aaaa<br><br>bbbb", $options];
         $data[] = [">aaaa \n>aaaa", "<blockquote>aaaaaaaa</blockquote>", $options];
         $data[] = [">aaaa\n>aaaa", "<blockquote>aaaa<br>aaaa</blockquote>", $options];
-        $data[] = [">aaaa \n>bbbb\ncccc dddd", "<blockquote>aaaabbbb</blockquote>>cccc_dddd<", $options];
+        $data[] = [">aaaa \n>bbbb\ncccc dddd", "<blockquote>aaaabbbb</blockquote>cccc dddd", $options];
 
         $options['flowed'] = false;
         $options['delsp']  = false;