diff --git a/src/Room.c b/src/Room.c
index 34f1161..bdd6398 100644
--- a/src/Room.c
+++ b/src/Room.c
@@ -605,6 +605,73 @@ AuthorizeInviteMembershipV1(Room * room, PduV1 pdu)
     return false;
 }
 static bool
+AuthorizeLeaveMembershipV1(Room * room, PduV1 pdu)
+{
+    int64_t ban_level = RoomMinPL(room, pdu.event_id, NULL, "ban");
+    int64_t kick_level = RoomMinPL(room, pdu.event_id, NULL, "kick");
+    int64_t sender_level = RoomUserPL(room, pdu.event_id, pdu.sender);
+    int64_t target_level = RoomUserPL(room, pdu.state_key, pdu.sender);
+    /* Step 5.4.1: If the sender matches state_key, allow if and only if 
+     * that user's current membership state is invite or join. */
+    if (StrEquals(pdu.sender, pdu.state_key))
+    {
+        return 
+            RoomUserHasMembership(room, pdu.event_id, pdu.sender, "invite") ||
+            RoomUserHasMembership(room, pdu.event_id, pdu.sender, "join");
+    }
+
+    /* Step 5.4.2: If the sender's current membership state is not join, 
+     * reject. */
+    if (!RoomUserHasMembership(room, pdu.event_id, pdu.sender, "join"))
+    {
+        return false;
+    }
+
+    /* Step 5.4.3: If the target user's current membership state is ban, 
+     * and the sender's power level is less than the ban level, reject. */
+    if (RoomUserHasMembership(room, pdu.event_id, pdu.state_key, "ban") &&
+        sender_level < ban_level)
+    {
+        return false;
+    }
+
+    /* Step 5.4.4: If the sender's power level is greater than or equal to 
+     * the kick level, and the target user's power level is less than the 
+     * sender's power level, allow. */
+    if ((sender_level >= kick_level) && target_level < sender_level)
+    {
+        return true;
+    }
+    
+    /* Step 5.4.5: Otherwise, reject. */
+    return false;
+}
+static bool
+AuthorizeBanMembershipV1(Room * room, PduV1 pdu)
+{
+    int64_t ban_pl, pdu_pl, target_pl;
+
+    /* Step 5.5.1: If the sender's current membership state is not join, reject. */
+    if (!RoomUserHasMembership(room, pdu.event_id, pdu.sender, "join"))
+    {
+        return false;
+    }
+
+    /* Step 5.5.2: If the sender's power level is greater than or equal 
+     * to the ban level, and the target user's power level is less than 
+     * the sender's power level, allow. */
+    ban_pl = RoomMinPL(room, pdu.event_id, NULL, "ban");
+    pdu_pl = RoomUserPL(room, pdu.event_id, pdu.sender);
+    target_pl = RoomUserPL(room, pdu.state_key, pdu.sender);
+    if ((pdu_pl >= ban_pl) && (target_pl < pdu_pl))
+    {
+        return true;
+    }
+
+    /* Step 5.5.3: Otherwise, reject. */
+    return false;
+}
+static bool
 AuthorizeJoinMembershipV1(Room * room, PduV1 pdu)
 {
     /* Step 5.2.1: If the only previous event is an m.room.create and the 
@@ -687,8 +754,14 @@ AuthoriseMemberV1(Room * room, PduV1 pdu)
     /* Step 5.2: If membership is join. */
     JumpIfMembership("join", AuthorizeJoinMembershipV1);
 
-    /* Step 5.3: If membership is invite. */
+    /* Step 5.3: If membership is invite. TODO */
     JumpIfMembership("invite", AuthorizeInviteMembershipV1);
+
+    /* Step 5.4: If membership is leave. */
+    JumpIfMembership("leave", AuthorizeLeaveMembershipV1);
+
+    /* Step 5.5: If membership is ban. */
+    JumpIfMembership("ban", AuthorizeBanMembershipV1);
     
     /* Step 5.6: Otherwise, the membership is unknown. Reject. */
     return false;