From 42cf52827226fab040277d346b82e2d7ad39c989 Mon Sep 17 00:00:00 2001
From: Nikitha Chettiar <nikithauc@gmail.com>
Date: Tue, 8 Jun 2021 12:00:48 -0700
Subject: [PATCH] Adding `customHosts` change

---
 changelogs/v3-upgrade-guide.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/changelogs/v3-upgrade-guide.md b/changelogs/v3-upgrade-guide.md
index d7217256c..c2e525a85 100644
--- a/changelogs/v3-upgrade-guide.md
+++ b/changelogs/v3-upgrade-guide.md
@@ -66,6 +66,17 @@
 ### Added `browser` field in package.json.
 - The `browser` field indicates the entry point for client applications using Microsoft Graph JS SDK library.
 
+### Added `customHosts` options
+- The `AuthenticationHandler` and `TelemetryHandler` will add or update the request headers only if the request URL is a Graph endpoint or a custom endpoint.
+- `customHosts` property in `IOptions`, `IClientOptions` takes in a `Set` of custom hosts.  
+
+```typescript
+// Consider the custom request url is https://CUSTOM_HOST.com
+const customHost = "CUSTOM_HOST";
+const customHosts = new Set<string>([customHost]);
+const client = Client.initWithMiddleware({ middleware, customHosts });
+```
+
 ### Added `GraphClientError`
 - `GraphClientError` handles client-side errors encountered within the JavaScript Client SDK whereas, `GraphError` class should be used to handle errors in the response from the Graph API.