diff --git a/tailbone/diffs.py b/tailbone/diffs.py
index f179128f..2771b7da 100644
--- a/tailbone/diffs.py
+++ b/tailbone/diffs.py
@@ -35,11 +35,12 @@ class Diff(object):
     Core diff class.  In sore need of documentation.
     """
 
-    def __init__(self, old_data, new_data, columns=None, fields=None, render_value=None, monospace=False):
+    def __init__(self, old_data, new_data, columns=None, fields=None, render_field=None, render_value=None, monospace=False):
         self.old_data = old_data
         self.new_data = new_data
         self.columns = columns or ["field name", "old value", "new value"]
         self.fields = fields or self.make_fields()
+        self._render_field = render_field or self.render_field_default
         self.render_value = render_value or self.render_value_default
         self.monospace = monospace
 
@@ -60,6 +61,12 @@ class Diff(object):
         context['diff'] = self
         return HTML.literal(render(template, context))
 
+    def render_field(self, field):
+        return self._render_field(field, self)
+
+    def render_field_default(self, field, diff):
+        return field
+
     def render_value_default(self, field, value):
         return repr(value)
 
diff --git a/tailbone/templates/diff.mako b/tailbone/templates/diff.mako
index 7f2132fd..4b8888e6 100644
--- a/tailbone/templates/diff.mako
+++ b/tailbone/templates/diff.mako
@@ -10,7 +10,7 @@
   <tbody>
     % for field in diff.fields:
        <tr${' class="diff"' if diff.values_differ(field) else ''|n}>
-         <td class="field">${field}</td>
+         <td class="field">${diff.render_field(field)}</td>
          <td class="old-value">${diff.render_old_value(field)}</td>
          <td class="new-value">${diff.render_new_value(field)}</td>
        </tr>
diff --git a/tailbone/views/upgrades.py b/tailbone/views/upgrades.py
index 60d5d484..c1423678 100644
--- a/tailbone/views/upgrades.py
+++ b/tailbone/views/upgrades.py
@@ -204,6 +204,7 @@ class UpgradeView(MasterView):
             after = self.parse_requirements(upgrade, 'after')
             diff = self.make_diff(before, after,
                                   columns=["package", "old version", "new version"],
+                                  render_field=self.render_diff_field,
                                   render_value=self.render_diff_value,
             )
             showing = HTML.tag('div',
@@ -216,6 +217,21 @@ class UpgradeView(MasterView):
         except:
             return "(not available for this upgrade)"
 
+    def render_diff_field(self, field, diff):
+        if field == 'rattail':
+            # TODO: use changelog from latest docs *unless* running from src
+            # url = 'https://rattailproject.org/buildbot/docs/rattail/changelog.html'
+            url = 'https://rattailproject.org/trac/log/rattail/?rev={}&stop_rev={}&limit=100'.format(
+                diff.new_value(field), diff.old_value(field))
+            return tags.link_to(field, url, target='_blank')
+        if field == 'Tailbone':
+            # TODO: use changelog from latest docs *unless* running from src
+            # url = 'https://rattailproject.org/buildbot/docs/tailbone/changelog.html'
+            url = 'https://rattailproject.org/trac/log/tailbone/?rev={}&stop_rev={}&limit=100'.format(
+                diff.new_value(field), diff.old_value(field))
+            return tags.link_to(field, url, target='_blank')
+        return field
+
     def render_diff_value(self, field, value):
         if value.startswith("u'") and value.endswith("'"):
             return value[2:1]