diff --git a/tailbone/views/upgrades.py b/tailbone/views/upgrades.py
index c1423678..9fbc6ac5 100644
--- a/tailbone/views/upgrades.py
+++ b/tailbone/views/upgrades.py
@@ -217,19 +217,36 @@ class UpgradeView(MasterView):
         except:
             return "(not available for this upgrade)"
 
+    def changelog_link(self, project, url):
+        return tags.link_to(project, url, target='_blank')
+
+    commit_hash_pattern = re.compile(r'^.{40}$')
+
+    def get_changelog_url(self, project, old_version, new_version):
+        projects = {
+            'rattail': 'rattail',
+            'Tailbone': 'tailbone',
+        }
+        if project not in projects:
+            return
+        if self.commit_hash_pattern.match(new_version):
+            if new_version == old_version:
+                return 'https://rattailproject.org/trac/log/{}/?rev={}&limit=100'.format(
+                    projects[project], new_version)
+            else:
+                return 'https://rattailproject.org/trac/log/{}/?rev={}&stop_rev={}&limit=100'.format(
+                    projects[project], new_version, old_version)
+        else:
+            # TODO: use changelog from latest docs
+            # return 'https://rattailproject.org/buildbot/docs/{}/changelog.html'.format(projects[project])
+            pass
+
     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')
+        old_version = diff.old_value(field)
+        new_version = diff.new_value(field)
+        url = self.get_changelog_url(field, old_version, new_version)
+        if url:
+            return self.changelog_link(field, url)
         return field
 
     def render_diff_value(self, field, value):