diff --git a/tools/make-chromium-meta.py b/tools/make-chromium-meta.py
index 319b7a1..f66c82e 100644
--- a/tools/make-chromium-meta.py
+++ b/tools/make-chromium-meta.py
@@ -20,15 +20,20 @@ manifest_out_file = os.path.join(build_dir, 'manifest.json')
 with open(manifest_out_file) as f:
     manifest_out = json.load(f)
 
-manifest_out['version'] = version
-
 # Development build? If so, modify name accordingly.
-match = re.search('^\d+\.\d+\.\d+\.\d+$', version)
+match = re.search('^(\d+\.\d+\.\d+)(\.|b|rc)(\d+)$', version)
 if match:
+    version = match.group(1)
+    revision = int(match.group(3))
+    if match.group(2) == 'rc':
+        revision += 100
+    version += '.' + str(revision)
     manifest_out['name'] += ' development build'
     manifest_out['short_name'] += ' dev build'
     manifest_out['browser_action']['default_title'] += ' dev build'
 
+manifest_out['version'] = version
+
 with open(manifest_out_file, 'w') as f:
     json.dump(manifest_out, f, indent=2, separators=(',', ': '), sort_keys=True)
     f.write('\n')