diff --git a/federation/hostmeta/parsers.py b/federation/hostmeta/parsers.py
index c2ef606..675549d 100644
--- a/federation/hostmeta/parsers.py
+++ b/federation/hostmeta/parsers.py
@@ -60,7 +60,8 @@ def parse_mastodon_document(doc, host):
     # TODO parse about page
     # https://github.com/TheKinrar/mastodon-instances/blob/master/tasks/update_instances.js#L508
     # result['open_signups']
-    version = [int(part) for part in doc.get('version', '').split('.')]
+    version = re.sub(r'[^0-9.]', '', doc.get('version', ''))
+    version = [int(part) for part in version.split('.')]
     if version >= [1, 6, 0]:
         result['protocols'] = ['ostatus', 'activitypub']
     else:
diff --git a/federation/tests/fixtures/hostmeta.py b/federation/tests/fixtures/hostmeta.py
index d947770..5baeaa2 100644
--- a/federation/tests/fixtures/hostmeta.py
+++ b/federation/tests/fixtures/hostmeta.py
@@ -17,6 +17,25 @@ MASTODON_DOC = """
                      "fields": []}}
 """
 
+MASTODON_RC_DOC = """
+{"uri": "mastodon.local", "title": "Mastodon",
+ "description": "This page describes the mastodon.local",
+ "email": "hello@mastodon.local", "version": "2.4.1rc1", "urls": {"streaming_api": "wss://mastodon.local"},
+ "stats": {"user_count": 159726, "status_count": 6059606, "domain_count": 4703},
+ "thumbnail": "https://files.mastodon.local/site_uploads/files/000/000/001/original/file.jpeg",
+ "languages": ["en"],
+ "contact_account": {"id": "1", "username": "Admin", "acct": "Admin", "display_name": "Admin dude", "locked": false,
+                     "bot": false, "created_at": "2016-03-16T14:34:26.392Z",
+                     "note": "\u003cp\u003eSuperuser\u003c/p\u003e",
+                     "url": "https://mastodon.local/@Admin",
+                     "avatar": "https://files.mastodon.local/accounts/avatars/000/000/001/original/file.png",
+                     "avatar_static": "https://files.mastodon.local/accounts/avatars/000/000/001/original/file.png",
+                     "header": "https://files.mastodon.local/accounts/headers/000/000/001/original/file.jpeg",
+                     "header_static": "https://files.mastodon.local/accounts/headers/000/000/001/original/file.jpeg",
+                     "followers_count": 81779, "following_count": 506, "statuses_count": 36722, "emojis": [],
+                     "fields": []}}
+"""
+
 MASTODON_ACTIVITY_DOC = """
     [
         {"week":"1526860800","statuses":"121188","logins":"8779","registrations":"1143"},
diff --git a/federation/tests/hostmeta/test_parsers.py b/federation/tests/hostmeta/test_parsers.py
index b7e2174..5dba14e 100644
--- a/federation/tests/hostmeta/test_parsers.py
+++ b/federation/tests/hostmeta/test_parsers.py
@@ -5,7 +5,8 @@ from federation.hostmeta.parsers import (
     parse_nodeinfo_document, parse_nodeinfo2_document, parse_statisticsjson_document, int_or_none,
     parse_mastodon_document)
 from federation.tests.fixtures.hostmeta import (
-    NODEINFO2_10_DOC, NODEINFO_10_DOC, NODEINFO_20_DOC, STATISTICS_JSON_DOC, MASTODON_DOC, MASTODON_ACTIVITY_DOC)
+    NODEINFO2_10_DOC, NODEINFO_10_DOC, NODEINFO_20_DOC, STATISTICS_JSON_DOC, MASTODON_DOC, MASTODON_ACTIVITY_DOC,
+    MASTODON_RC_DOC)
 
 
 class TestIntOrNone:
@@ -46,6 +47,38 @@ class TestParseMastodonDocument:
             },
         }
 
+    @patch('federation.hostmeta.parsers.fetch_document')
+    def test_parse_mastodon_document__rc_version(self, mock_fetch):
+        mock_fetch.return_value = MASTODON_ACTIVITY_DOC, 200, None
+        result = parse_mastodon_document(json.loads(MASTODON_RC_DOC), 'example.com')
+        assert result == {
+            'organization': {
+                'account': 'https://mastodon.local/@Admin',
+                'contact': 'hello@mastodon.local',
+                'name': 'Admin dude',
+            },
+            'host': 'example.com',
+            'name': 'Mastodon',
+            'open_signups': False,
+            'protocols': ["ostatus", "activitypub"],
+            'relay': False,
+            'server_meta': {},
+            'services': [],
+            'platform': 'mastodon',
+            'version': '2.4.1rc1',
+            'features': {},
+            'activity': {
+                'users': {
+                    'total': 159726,
+                    'half_year': 90774,
+                    'monthly': 27829,
+                    'weekly': 8779,
+                },
+                'local_posts': None,
+                'local_comments': None,
+            },
+        }
+
 
 class TestParseNodeInfoDocument:
     def test_parse_nodeinfo_10_document(self):