diff --git a/apn/apn-test.ts b/apn/apn-test.ts
index a9e2c21a7..b47259d76 100644
--- a/apn/apn-test.ts
+++ b/apn/apn-test.ts
@@ -50,7 +50,7 @@ var feedbackService = new apn.Feedback({
 feedbackService.on("error", (error:Error) => {
 	console.log("push feedback error", error.name, error.message);
 });
-function processFeedbackData(device:Buffer, time:number) {
+function processFeedbackData(device:apn.Device, time:number) {
 }
 feedbackService.on("feedback", (feedbackData) => {
 	feedbackData.forEach((data) => {
@@ -135,7 +135,7 @@ pushSomeNotifications();
 
 function handleFeedback(feedbackData:apn.FeedbackData[]) {
 	feedbackData.forEach(function(feedbackItem) {
-		console.log("Device: " + feedbackItem.device.toString("hex") + " has been unreachable, since: " + feedbackItem.time);
+		console.log("Device: " + feedbackItem.device.toString() + " has been unreachable, since: " + feedbackItem.time);
 	});
 }
 
diff --git a/apn/apn.d.ts b/apn/apn.d.ts
index ed38086ef..cd67743da 100644
--- a/apn/apn.d.ts
+++ b/apn/apn.d.ts
@@ -307,7 +307,7 @@ declare module "apn" {
 	}
 	export interface FeedbackData {
 		time:number;
-		device:Buffer;
+		device:Device;
 	}
 	/**
 	 * Connection to the Apple Push Notification Feedback Service and if `interval` isn't disabled automatically begins polling the service. Many of the options are the same as `apn.Connection()`