diff --git a/API-Protocol.md b/API-Protocol.md
index e3c3b0a..0550181 100644
--- a/API-Protocol.md
+++ b/API-Protocol.md
@@ -192,11 +192,12 @@ message PushMessageContent {
 If a client does not have an existing session with a recipient, the client will need to retrieve a PreKey for the recipient in order to start one.
 
 ```
-GET /v1/keys/{number}?relay={relay}
+GET /v1/keys/{number}/{device_id}?relay={relay}
 Authorization: Basic {basic_auth}
 ```
 
-1. `number` is the PSTN number of the recipient.
+1. `number` is the number of the recipient.
+1. `device_id` is the device id of the recipient, or `*` for all devices.
 1. `relay` (optional) is the federated relay the recipient is associated with.  The `relay` param should only be included if the destination is at a federated node other than the sender.
 
 **Returns**:
@@ -208,9 +209,15 @@ Authorization: Basic {basic_auth}
 
 ```
 {
-  keyId: {key_id},
-  publicKey: "{public_key}",
-  identityKey: "{public_key}"
+  "keys" : [
+    {
+      "deviceId": {device_id},
+      "keyId": {key_id},
+      "publicKey": "{public_key}",
+      "identityKey": "{public_key}"    
+    },
+    ...
+  ]
 }
 ```