diff --git a/h1/models.py b/h1/models.py
index 81e43e1..d17ac4f 100644
--- a/h1/models.py
+++ b/h1/models.py
@@ -492,6 +492,10 @@ class ActivityCommentsClosed(ActivityBase):
     TYPE = "activity-comments-closed"
 
 
+class ActivityCveIdAdded(ActivityBase):
+    TYPE = "activity-cve-id-added"
+
+
 class ActivityExternalUserInvitationCancelled(ActivityBase):
     TYPE = "activity-external-user-invitation-cancelled"
 
@@ -510,7 +514,7 @@ class ActivityExternalUserJoined(ActivityBase):
     TYPE = "activity-external-user-joined"
 
     def _activity_hydrate(self):
-        self._make_attribute("duplicate_report_id", self._hydrate_verbatim)
+        self._make_attribute("duplicate_report_id", self._hydrate_verbatim, optional=True)
 
 
 class ActivityExternalUserRemoved(ActivityBase):
@@ -539,6 +543,10 @@ class ActivityMediationRequested(ActivityBase):
     TYPE = "activity-mediation-requested"
 
 
+class ActivityNobodyAssignedToBug(ActivityBase):
+    TYPE = "activity-nobody-assigned-to-bug"
+
+
 class ActivityNotEligibleForBounty(ActivityBase):
     TYPE = "activity-not-eligible-for-bounty"
 
diff --git a/tests/resources/activity-cve-id-added.json b/tests/resources/activity-cve-id-added.json
new file mode 100644
index 0000000..dd4adbb
--- /dev/null
+++ b/tests/resources/activity-cve-id-added.json
@@ -0,0 +1,30 @@
+{
+    "type": "activity-cve-id-added",
+    "id": "1337",
+    "attributes": {
+        "message": "",
+        "created_at": "2016-02-02T04:05:06.000Z",
+        "updated_at": "2016-02-02T04:05:06.000Z",
+        "internal": false
+    },
+    "relationships": {
+        "actor": {
+            "data": {
+                "type": "user",
+                "id": "1337",
+                "attributes": {
+                    "username": "api-example",
+                    "name": "API Example",
+                    "disabled": false,
+                    "created_at": "2016-02-02T04:05:06.000Z",
+                    "profile_picture": {
+                      "62x62": "/assets/avatars/default.png",
+                      "82x82": "/assets/avatars/default.png",
+                      "110x110": "/assets/avatars/default.png",
+                      "260x260": "/assets/avatars/default.png"
+                    }
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/tests/resources/activity-nobody-assigned-to-bug.json b/tests/resources/activity-nobody-assigned-to-bug.json
new file mode 100644
index 0000000..640876a
--- /dev/null
+++ b/tests/resources/activity-nobody-assigned-to-bug.json
@@ -0,0 +1,30 @@
+{
+    "type": "activity-nobody-assigned-to-bug",
+    "id": "1337",
+    "attributes": {
+        "message": "",
+        "created_at": "2016-02-02T04:05:06.000Z",
+        "updated_at": "2016-02-02T04:05:06.000Z",
+        "internal": false
+    },
+    "relationships": {
+        "actor": {
+            "data": {
+                "type": "user",
+                "id": "1337",
+                "attributes": {
+                    "username": "api-example",
+                    "name": "API Example",
+                    "disabled": false,
+                    "created_at": "2016-02-02T04:05:06.000Z",
+                    "profile_picture": {
+                      "62x62": "/assets/avatars/default.png",
+                      "82x82": "/assets/avatars/default.png",
+                      "110x110": "/assets/avatars/default.png",
+                      "260x260": "/assets/avatars/default.png"
+                    }
+                }
+            }
+        }
+    }
+}
\ No newline at end of file