diff --git a/package.json b/package.json
index 9e6d930..7974c70 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@flagsync/node-sdk",
-  "version": "0.2.3",
+  "version": "0.2.4-alpha.0",
   "description": "FlagSync SDK for Node.js",
   "author": "Mike Chabot",
   "license": "Apache-2.0",
@@ -62,6 +62,6 @@
     "axios": "^1.7.2",
     "deepmerge": "^4.3.1",
     "eventemitter3": "^5.0.1",
-    "extended-eventsource": "^1.4.9"
+    "eventsource": "^4.0.0"
   }
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d6a5a46..8c8d5a4 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -14,9 +14,9 @@ dependencies:
   eventemitter3:
     specifier: ^5.0.1
     version: 5.0.1
-  extended-eventsource:
-    specifier: ^1.4.9
-    version: 1.4.9
+  eventsource:
+    specifier: ^4.0.0
+    version: 4.0.0
 
 devDependencies:
   '@trivago/prettier-plugin-sort-imports':
@@ -1618,6 +1618,18 @@ packages:
     resolution: {integrity: sha512-GWkBvjiSZK87ELrYOSESUYeVIc9mvLLf/nXalMOS5dYrgZq9o5OVkbZAVM06CVxYsCwH9BDZFPlQTlPA1j4ahA==}
     dev: false
 
+  /eventsource-parser@3.0.2:
+    resolution: {integrity: sha512-6RxOBZ/cYgd8usLwsEl+EC09Au/9BcmCKYF2/xbml6DNczf7nv0MQb+7BA2F+li6//I+28VNlQR37XfQtcAJuA==}
+    engines: {node: '>=18.0.0'}
+    dev: false
+
+  /eventsource@4.0.0:
+    resolution: {integrity: sha512-fvIkb9qZzdMxgZrEQDyll+9oJsyaVvY92I2Re+qK0qEJ+w5s0X3dtz+M0VAPOjP1gtU3iqWyjQ0G3nvd5CLZ2g==}
+    engines: {node: '>=20.0.0'}
+    dependencies:
+      eventsource-parser: 3.0.2
+    dev: false
+
   /execa@5.1.1:
     resolution: {integrity: sha512-8uSpZZocAZRBAPIEINJj3Lo9HyGitllczc27Eh5YYojjMFMn8yHMDMaUHE2Jqfq05D/wucwI4JGURyXt1vchyg==}
     engines: {node: '>=10'}
@@ -1648,10 +1660,6 @@ packages:
       strip-final-newline: 3.0.0
     dev: true
 
-  /extended-eventsource@1.4.9:
-    resolution: {integrity: sha512-x0SMAw57jEaiBKLQWTatVBZkT/PRuL5hdiEP6s8GKqeQOapBRwnohI6e8zGM0XStolQrQe+L6Wvin8G0UthRbw==}
-    dev: false
-
   /fast-deep-equal@3.1.3:
     resolution: {integrity: sha512-f3qQ9oQy9j2AhBe/H9VC91wLmKBCCU/gDOnKNAYG5hswO7BLKj09Hc5HYNz9cGI++xlpDCIgDaitVs03ATR84Q==}
     dev: true
diff --git a/src/managers/sync/stream-manager.ts b/src/managers/sync/stream-manager.ts
index 3408a26..3ad10dc 100644
--- a/src/managers/sync/stream-manager.ts
+++ b/src/managers/sync/stream-manager.ts
@@ -1,4 +1,4 @@
-import { EventSource } from 'extended-eventsource';
+import { EventSource } from 'eventsource';
 
 import { FsFlagSet } from '~config/types';
 import { FsSettings } from '~config/types.internal';
@@ -23,17 +23,18 @@ export const streamManager = (
     /**
      * Create a new EventSource instance and listen for incoming flag updates.
      */
-    es = new EventSource(
-      `${urls.sdk}/sse/sdk-updates/server?timestamp=${new Date().getTime()}`,
-      {
-        withCredentials: true,
-        disableLogger: true,
-        headers: {
-          'x-ridgeline-key': settings.sdkKey,
-          'x-ridgeline-sdk-ctx': JSON.stringify(sdkContext),
-        },
-      },
-    );
+    es = new EventSource(`${urls.sdk}/sse/sdk-updates/server`, {
+      withCredentials: true,
+      fetch: (input, init) =>
+        fetch(input, {
+          ...init,
+          headers: {
+            ...init.headers,
+            'x-ridgeline-key': settings.sdkKey,
+            'x-ridgeline-sdk-ctx': JSON.stringify(sdkContext),
+          },
+        }),
+    });
 
     /**
      * For debug only