diff -r 177b186dd23a roundup/cgi/templating.py
--- a/roundup/cgi/templating.py	Fri Oct 23 18:38:37 2020 -0400
+++ b/roundup/cgi/templating.py	Sat Oct 24 17:34:32 2020 +0200
@@ -69,7 +69,13 @@
             # don't allow disabled protocols in links
             _safe_protocols = re.compile('(?!' + ':|'.join([re.escape(s) for s in _disable_url_schemes]) + ':)', re.IGNORECASE)
 
-        markdown = lambda s: Markdown(safe_mode='escape', extras={ 'fenced-code-blocks' : True }).convert(s)
+        def _extras(config):
+            extras = { 'fenced-code-blocks' : True }
+            if config['MARKDOWN_BREAK_ON_NEWLINE']:
+                extras['break-on-newline'] = True
+            return extras
+
+        markdown = lambda s, c: Markdown(safe_mode='escape', extras=_extras(c)).convert(s)
     except ImportError:
         markdown = None
 
@@ -107,7 +113,13 @@
                 else:
                     md.treeprocessors['restrict_links'] = RestrictLinksProcessor()
 
-        markdown = lambda s: markdown_impl(s, extensions=[SafeHtml(), 'fenced_code'])
+        def _extensions(config):
+            extensions = [SafeHtml(), 'fenced_code']
+            if config['MARKDOWN_BREAK_ON_NEWLINE']:
+                extensions.append('nl2br')
+            return extensions
+
+        markdown = lambda s, c: markdown_impl(s, extensions=_extensions(c))
     except ImportError:
         markdown = None
 
@@ -117,7 +129,14 @@
     try:
         import mistune
         mistune._scheme_blacklist = [ s + ':' for s in _disable_url_schemes ]
-        markdown = mistune.markdown
+
+        def _options(config):
+            options = {}
+            if config['MARKDOWN_BREAK_ON_NEWLINE']:
+                options['hard_wrap'] = True
+            return options
+
+        markdown = lambda s, c: mistune.markdown(s, **_options(c))
     except ImportError:
         markdown = None
 
@@ -1731,8 +1750,9 @@
         if hyperlink:
             s = self.hyper_re.sub(self._hyper_repl_markdown, s)
         try:
-            s = u2s(markdown(s2u(s)))
+            s = u2s(markdown(s2u(s), self._db.config))
         except Exception:  # when markdown formatting fails return markup
+            raise
             return self.plain(escape=0, hyperlink=hyperlink)
         return s
 
diff -r 177b186dd23a roundup/configuration.py
--- a/roundup/configuration.py	Fri Oct 23 18:38:37 2020 -0400
+++ b/roundup/configuration.py	Sat Oct 24 17:34:32 2020 +0200
@@ -1329,6 +1329,10 @@
             "won't be attached to nosy mails. They will be replaced by\n"
             "a link to the tracker's download page for the file.")
     ), "Nosy messages sending"),
+    ("markdown", (
+        (BooleanOption, "break_on_newline", "no",
+            "Replace single new line characters with <br>?"),
+    ), "Markdown rendering options."),
 )
 
 ### Configuration classes
diff -r 177b186dd23a share/roundup/templates/jinja2/html/issue.item.html
--- a/share/roundup/templates/jinja2/html/issue.item.html	Fri Oct 23 18:38:37 2020 -0400
+++ b/share/roundup/templates/jinja2/html/issue.item.html	Sat Oct 24 17:34:32 2020 +0200
@@ -32,7 +32,7 @@
       var node = $('#change_note')[0];
       var initSimpleMde = function () {
         node.parentNode.appendChild($('<input/>', { type: 'hidden', name: 'msg-1@type', value: 'text/markdown'})[0]);
-        var simplemde = new SimpleMDE({ element: node, status: false, styleSelectedText: false, renderingConfig: {singleLineBreaks: false}});
+        var simplemde = new SimpleMDE({ element: node, status: false, styleSelectedText: false, renderingConfig: {singleLineBreaks: Boolean({{ config.MARKDOWN_BREAK_ON_NEWLINE }}) }});
         simplemde.render();
       };
       {% if context.id %}
diff -r 177b186dd23a test/test_templating.py
--- a/test/test_templating.py	Fri Oct 23 18:38:37 2020 -0400
+++ b/test/test_templating.py	Sat Oct 24 17:34:32 2020 +0200
@@ -1,6 +1,7 @@
 from __future__ import print_function
 import unittest
 from cgi import FieldStorage, MiniFieldStorage
+from operator import setitem
 
 from roundup.cgi.templating import *
 from .test_actions import MockNull, true
@@ -74,7 +75,7 @@
         # add client props for testing anti_csrf_nonce
         self.client.session_api = MockNull(_sid="1234567890")
         self.client.db.getuid = lambda : 10
-        self.client.db.config = {'WEB_CSRF_TOKEN_LIFETIME': 10 }
+        self.client.db.config = {'WEB_CSRF_TOKEN_LIFETIME': 10, 'MARKDOWN_BREAK_ON_NEWLINE': False }
 
 class HTMLDatabaseTestCase(TemplatingTestCase):
     def test_HTMLDatabase___getitem__(self):
@@ -477,6 +478,16 @@
               # so processing it returns original text
             self.assertEqual(m.replace('\n\n', '\n'), u2s(u'embedded code block &lt;pre&gt;\n``` python\nline 1\nline 2\n```\nnew &lt;/pre&gt; paragraph'))
 
+    def test_break_on_newline(self):
+        self.client.db.config['MARKDOWN_BREAK_ON_NEWLINE'] = True
+        p = StringHTMLProperty(self.client, 'test', '1', None, 'test', u2s(u'A string with\nline break'))
+        m = p.markdown()
+        self.assertEqual(1, m.count('<br'))
+        self.client.db.config['MARKDOWN_BREAK_ON_NEWLINE'] = False
+
+        m = p.markdown()
+        self.assertEqual(0, m.count('<br'))
+
 
 @skip_mistune
 class MistuneTestCase(TemplatingTestCase, MarkdownTests) :