diff --git a/src/metrics.ts b/src/metrics.ts
index 45d20996..9030ba52 100644
--- a/src/metrics.ts
+++ b/src/metrics.ts
@@ -11,6 +11,7 @@ import { SUPPORTED_SPEC_VERSION } from './repository';
 export interface MetricsOptions {
   appName: string;
   instanceId: string;
+  connectionId: string;
   strategies: string[];
   metricsInterval: number;
   metricsJitter?: number;
@@ -80,6 +81,8 @@ export default class Metrics extends EventEmitter {
 
   private instanceId: string;
 
+  private connectionId: string;
+
   private sdkVersion: string;
 
   private strategies: string[];
@@ -111,6 +114,7 @@ export default class Metrics extends EventEmitter {
   constructor({
     appName,
     instanceId,
+    connectionId,
     strategies,
     metricsInterval = 0,
     metricsJitter = 0,
@@ -127,6 +131,7 @@ export default class Metrics extends EventEmitter {
     this.metricsJitter = metricsJitter;
     this.appName = appName;
     this.instanceId = instanceId;
+    this.connectionId = connectionId;
     this.sdkVersion = sdkVersion;
     this.strategies = strategies;
     this.url = url;
@@ -198,6 +203,7 @@ export default class Metrics extends EventEmitter {
         json: payload,
         appName: this.appName,
         instanceId: this.instanceId,
+        connectionId: this.connectionId,
         headers,
         timeout: this.timeout,
         httpOptions: this.httpOptions,
@@ -250,6 +256,7 @@ export default class Metrics extends EventEmitter {
         json: payload,
         appName: this.appName,
         instanceId: this.instanceId,
+        connectionId: this.connectionId,
         headers,
         timeout: this.timeout,
         httpOptions: this.httpOptions,
diff --git a/src/repository/bootstrap-provider.ts b/src/repository/bootstrap-provider.ts
index 5918e0d1..354d8514 100644
--- a/src/repository/bootstrap-provider.ts
+++ b/src/repository/bootstrap-provider.ts
@@ -48,7 +48,13 @@ export class DefaultBootstrapProvider implements BootstrapProvider {
     const response = await fetch(bootstrapUrl, {
       method: 'GET',
       timeout: 10_000,
-      headers: buildHeaders(this.appName, this.instanceId, undefined, undefined, this.urlHeaders),
+      headers: buildHeaders({
+        appName: this.appName,
+        instanceId: this.instanceId,
+        etag: undefined,
+        contentType: undefined,
+        custom: this.urlHeaders,
+      }),
       retry: {
         retries: 2,
         maxTimeout: 10_000,
diff --git a/src/repository/index.ts b/src/repository/index.ts
index 97571ad6..ff7d6f75 100644
--- a/src/repository/index.ts
+++ b/src/repository/index.ts
@@ -30,6 +30,7 @@ export interface RepositoryOptions {
   url: string;
   appName: string;
   instanceId: string;
+  connectionId: string;
   projectName?: string;
   refreshInterval: number;
   timeout?: number;
@@ -59,6 +60,8 @@ export default class Repository extends EventEmitter implements EventEmitter {
 
   private instanceId: string;
 
+  private connectionId: string;
+
   private refreshInterval: number;
 
   private headers?: CustomHeaders;
@@ -101,6 +104,7 @@ export default class Repository extends EventEmitter implements EventEmitter {
     url,
     appName,
     instanceId,
+    connectionId,
     projectName,
     refreshInterval = 15_000,
     timeout,
@@ -118,6 +122,7 @@ export default class Repository extends EventEmitter implements EventEmitter {
     this.url = url;
     this.refreshInterval = refreshInterval;
     this.instanceId = instanceId;
+    this.connectionId = connectionId;
     this.appName = appName;
     this.projectName = projectName;
     this.headers = headers;
@@ -386,6 +391,7 @@ Message: ${err.message}`,
         appName: this.appName,
         timeout: this.timeout,
         instanceId: this.instanceId,
+        connectionId: this.connectionId,
         headers,
         httpOptions: this.httpOptions,
         supportedSpecVersion: SUPPORTED_SPEC_VERSION,
diff --git a/src/request.ts b/src/request.ts
index 15186ca5..1a607cb3 100644
--- a/src/request.ts
+++ b/src/request.ts
@@ -7,6 +7,7 @@ import { URL } from 'url';
 import { getProxyForUrl } from 'proxy-from-env';
 import { CustomHeaders } from './headers';
 import { HttpOptions } from './http-options';
+const details = require('./details.json');
 
 export interface RequestOptions {
   url: string;
@@ -18,6 +19,7 @@ export interface GetRequestOptions extends RequestOptions {
   etag?: string;
   appName?: string;
   instanceId?: string;
+  connectionId: string;
   supportedSpecVersion?: string;
   httpOptions?: HttpOptions;
 }
@@ -30,6 +32,7 @@ export interface PostRequestOptions extends RequestOptions {
   json: Data;
   appName?: string;
   instanceId?: string;
+  connectionId?: string;
   httpOptions?: HttpOptions;
 }
 
@@ -55,18 +58,35 @@ export const getDefaultAgent = (url: URL) => {
     : new HttpProxyAgent(proxy, httpAgentOptions);
 };
 
-export const buildHeaders = (
-  appName?: string,
-  instanceId?: string,
-  etag?: string,
-  contentType?: string,
-  custom?: CustomHeaders,
-  specVersionSupported?: string,
-): Record<string, string> => {
+type HeaderOptions = {
+  appName?: string;
+  instanceId?: string;
+  etag?: string;
+  contentType?: string;
+  custom?: CustomHeaders;
+  specVersionSupported?: string;
+  connectionId?: string;
+};
+
+export const buildHeaders = ({
+  appName,
+  instanceId,
+  etag,
+  contentType,
+  custom,
+  specVersionSupported,
+  connectionId,
+}: HeaderOptions): Record<string, string> => {
   const head: Record<string, string> = {};
   if (appName) {
+    // TODO: delete
     head['UNLEASH-APPNAME'] = appName;
+    // TODO: delete
     head['User-Agent'] = appName;
+    head['x-unleash-appname'] = appName;
+  }
+  if (connectionId) {
+    head['x-unleash-connection-id'] = connectionId;
   }
   if (instanceId) {
     head['UNLEASH-INSTANCEID'] = instanceId;
@@ -80,6 +100,8 @@ export const buildHeaders = (
   if (specVersionSupported) {
     head['Unleash-Client-Spec'] = specVersionSupported;
   }
+  const version = details.version;
+  head['x-unleash-sdk'] = `unleash-node@${version}`;
   if (custom) {
     Object.assign(head, custom);
   }
@@ -91,6 +113,7 @@ export const post = ({
   appName,
   timeout,
   instanceId,
+  connectionId,
   headers,
   json,
   httpOptions,
@@ -99,7 +122,14 @@ export const post = ({
     timeout: timeout || 10000,
     method: 'POST',
     agent: httpOptions?.agent || getDefaultAgent,
-    headers: buildHeaders(appName, instanceId, undefined, 'application/json', headers),
+    headers: buildHeaders({
+      appName,
+      instanceId,
+      connectionId,
+      etag: undefined,
+      contentType: 'application/json',
+      custom: headers,
+    }),
     body: JSON.stringify(json),
     strictSSL: httpOptions?.rejectUnauthorized,
   });
@@ -110,6 +140,7 @@ export const get = ({
   appName,
   timeout,
   instanceId,
+  connectionId,
   headers,
   httpOptions,
   supportedSpecVersion,
@@ -118,7 +149,15 @@ export const get = ({
     method: 'GET',
     timeout: timeout || 10_000,
     agent: httpOptions?.agent || getDefaultAgent,
-    headers: buildHeaders(appName, instanceId, etag, undefined, headers, supportedSpecVersion),
+    headers: buildHeaders({
+      appName,
+      instanceId,
+      etag,
+      contentType: undefined,
+      custom: headers,
+      specVersionSupported: supportedSpecVersion,
+      connectionId,
+    }),
     retry: {
       retries: 2,
       maxTimeout: timeout || 10_000,
diff --git a/src/test/metrics.test.ts b/src/test/metrics.test.ts
index 7d4980ac..1b545aa4 100644
--- a/src/test/metrics.test.ts
+++ b/src/test/metrics.test.ts
@@ -122,17 +122,27 @@ test('should sendMetrics', async (t) => {
   t.true(metricsEP.isDone());
 });
 
-test('should send custom headers', (t) =>
+test('should send correct custom and x-unleash headers', (t) =>
   new Promise((resolve) => {
     const url = getUrl();
     t.plan(2);
     const randomKey = `value-${Math.random()}`;
-    const metricsEP = nockMetrics(url).matchHeader('randomKey', randomKey);
-    const regEP = nockRegister(url).matchHeader('randomKey', randomKey);
+    const metricsEP = nockMetrics(url)
+      .matchHeader('randomKey', randomKey)
+      .matchHeader('x-unleash-appname', 'appName')
+      .matchHeader('x-unleash-sdk', /^unleash-node@(\d+\.\d+\.\d+)$/)
+      .matchHeader('x-unleash-connection-id', 'connectionId');
+    const regEP = nockRegister(url)
+      .matchHeader('randomKey', randomKey)
+      .matchHeader('x-unleash-appname', 'appName')
+      .matchHeader('x-unleash-sdk', /^unleash-node@(\d+\.\d+\.\d+)$/)
+      .matchHeader('x-unleash-connection-id', 'connectionId');
 
     // @ts-expect-error
     const metrics = new Metrics({
       url,
+      appName: 'appName',
+      connectionId: 'connectionId',
       metricsInterval: 50,
       headers: {
         randomKey,
@@ -259,6 +269,7 @@ test('sendMetrics should backoff on 404', async (t) => {
   const metrics = new Metrics({
     appName: '404-tester',
     instanceId: '404-instance',
+    connectionId: '404-connection',
     metricsInterval: 10,
     strategies: [],
     url,
@@ -449,6 +460,7 @@ test('sendMetrics should stop on 401', async (t) => {
   const metrics = new Metrics({
     appName: '401-tester',
     instanceId: '401-instance',
+    connectionId: '401-connection',
     metricsInterval: 0,
     strategies: [],
     url,
@@ -465,6 +477,7 @@ test('sendMetrics should stop on 403', async (t) => {
   const metrics = new Metrics({
     appName: '401-tester',
     instanceId: '401-instance',
+    connectionId: '401-connection',
     metricsInterval: 0,
     strategies: [],
     url,
@@ -481,6 +494,7 @@ test('sendMetrics should backoff on 429', async (t) => {
   const metrics = new Metrics({
     appName: '429-tester',
     instanceId: '429-instance',
+    connectionId: '429-connection',
     metricsInterval: 10,
     strategies: [],
     url,
@@ -504,6 +518,7 @@ test('sendMetrics should backoff on 500', async (t) => {
   const metrics = new Metrics({
     appName: '500-tester',
     instanceId: '500-instance',
+    connectionId: '500-connetion',
     metricsInterval: 10,
     strategies: [],
     url,
@@ -528,6 +543,7 @@ test('sendMetrics should backoff on 429 and gradually reduce interval', async (t
   const metrics = new Metrics({
     appName: '429-tester',
     instanceId: '429-instance',
+    connectionId: '429-connection',
     metricsInterval,
     strategies: [],
     url,
diff --git a/src/test/repository.test.ts b/src/test/repository.test.ts
index 00a15623..7e31db0f 100644
--- a/src/test/repository.test.ts
+++ b/src/test/repository.test.ts
@@ -14,6 +14,7 @@ import { EventEmitter } from 'events';
 
 const appName = 'foo';
 const instanceId = 'bar';
+const connectionId = 'baz';
 
 // @ts-expect-error
 function setup(url, toggles, headers = {}) {
@@ -37,6 +38,7 @@ test('should fetch from endpoint', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -66,6 +68,7 @@ test('should poll for changes', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -98,6 +101,7 @@ test('should retry even if custom header function fails', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       customHeadersFunction: () => {
         throw new Error('custom function fails');
@@ -129,6 +133,7 @@ test('should store etag', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -158,6 +163,7 @@ test('should request with etag', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -177,12 +183,15 @@ test('should request with etag', (t) =>
     repo.start();
   }));
 
-test('should request with custom headers', (t) =>
+test('should request with correct custom and x-unleash headers', (t) =>
   new Promise((resolve) => {
     const url = 'http://unleash-test-4-x.app';
     const randomKey = `random-${Math.random()}`;
     nock(url)
       .matchHeader('randomKey', randomKey)
+      .matchHeader('x-unleash-appname', appName)
+      .matchHeader('x-unleash-connection-id', connectionId)
+      .matchHeader('x-unleash-sdk', /^unleash-node@(\d+\.\d+\.\d+)$/)
       .persist()
       .get('/client/features')
       .reply(200, { features: [] }, { Etag: '12345-3' });
@@ -191,6 +200,7 @@ test('should request with custom headers', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -229,6 +239,7 @@ test('request with customHeadersFunction should take precedence over customHeade
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -259,6 +270,7 @@ test('should handle 429 request error and emit warn event', async (t) => {
     url,
     appName,
     instanceId,
+    connectionId,
     refreshInterval: 10,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -291,6 +303,7 @@ test('should handle 401 request error and emit error event', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -317,6 +330,7 @@ test('should handle 403 request error and emit error event', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -343,6 +357,7 @@ test('should handle 500 request error and emit warn event', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -363,6 +378,7 @@ test.skip('should handle 502 request error and emit warn event', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -383,6 +399,7 @@ test.skip('should handle 503 request error and emit warn event', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -403,6 +420,7 @@ test.skip('should handle 504 request error and emit warn event', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 10,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -427,6 +445,7 @@ test('should handle 304 as silent ok', (t) => {
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -449,6 +468,7 @@ test('should handle invalid JSON response', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
       storageProvider: new InMemStorageProvider(),
@@ -508,6 +528,7 @@ test('should emit errors on invalid features', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
       storageProvider: new InMemStorageProvider(),
@@ -541,6 +562,7 @@ test('should emit errors on invalid variant', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
       storageProvider: new InMemStorageProvider(),
@@ -603,6 +625,7 @@ test('should load bootstrap first if faster than unleash-api', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({ url: bootstrap }),
       storageProvider: new InMemStorageProvider(),
@@ -669,6 +692,7 @@ test('bootstrap should not override actual data', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({ url: bootstrap }),
       storageProvider: new InMemStorageProvider(),
@@ -717,6 +741,7 @@ test('should load bootstrap first from file', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({ filePath: path }),
@@ -743,6 +768,7 @@ test('should not crash on bogus bootstrap', (t) =>
       url,
       appName,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({ filePath: path }),
@@ -788,6 +814,7 @@ test('should load backup-file', (t) =>
       url,
       appName: appNameLocal,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -834,6 +861,7 @@ test('bootstrap should override load backup-file', (t) =>
       url,
       appName: appNameLocal,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       disableFetch: true,
@@ -914,6 +942,7 @@ test('bootstrap should not override load backup-file', async (t) => {
     url,
     appName: appNameLocal,
     instanceId,
+    connectionId,
     refreshInterval: 0,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({
@@ -942,6 +971,7 @@ test.skip('Failing two times and then succeed should decrease interval to 2 time
     url,
     appName,
     instanceId,
+    connectionId,
     refreshInterval: 10,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -990,6 +1020,7 @@ test.skip('Failing two times should increase interval to 3 times initial interva
     url,
     appName,
     instanceId,
+    connectionId,
     refreshInterval: 10,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -1013,6 +1044,7 @@ test.skip('Failing two times and then succeed should decrease interval to 2 time
     url,
     appName,
     instanceId,
+    connectionId,
     refreshInterval: 10,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -1128,6 +1160,7 @@ test('should handle not finding a given segment id', (t) =>
       url,
       appName: appNameLocal,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       disableFetch: true,
@@ -1189,6 +1222,7 @@ test('should handle not having segments to read from', (t) =>
       url,
       appName: appNameLocal,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       disableFetch: true,
@@ -1284,6 +1318,7 @@ test('should return full segment data when requested', (t) =>
       url,
       appName: appNameLocal,
       instanceId,
+      connectionId,
       refreshInterval: 0,
       // @ts-expect-error
       disableFetch: true,
@@ -1316,6 +1351,7 @@ test('Stopping repository should stop unchanged event reporting', async (t) => {
     url,
     appName,
     instanceId,
+    connectionId,
     refreshInterval: 10,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -1348,6 +1384,7 @@ test('Stopping repository should stop storage provider updates', async (t) => {
     url,
     appName,
     instanceId,
+    connectionId,
     refreshInterval: 10,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({}),
@@ -1396,6 +1433,7 @@ test('Streaming', async (t) => {
     url,
     appName,
     instanceId,
+    connectionId,
     refreshInterval: 10,
     // @ts-expect-error
     bootstrapProvider: new DefaultBootstrapProvider({}),
diff --git a/src/test/request.test.ts b/src/test/request.test.ts
index 5425b7a6..f131aa1d 100644
--- a/src/test/request.test.ts
+++ b/src/test/request.test.ts
@@ -14,9 +14,20 @@ test('https URLs should yield https.Agent', (t) => {
   t.true(agent instanceof https.Agent);
 });
 
-test('Custom headers should be included', (t) => {
-  const headers = buildHeaders('https://bullshit.com', undefined, undefined, undefined, {
-    hello: 'world',
+test('Correct headers should be included', (t) => {
+  const headers = buildHeaders({
+    appName: 'myApp',
+    instanceId: 'instanceId',
+    etag: undefined,
+    contentType: undefined,
+    connectionId: 'connectionId',
+    custom: {
+      hello: 'world',
+    },
   });
   t.is(headers.hello, 'world');
+  t.is(headers['UNLEASH-INSTANCEID'], 'instanceId');
+  t.is(headers['x-unleash-connection-id'], 'connectionId');
+  t.is(headers['x-unleash-appname'], 'myApp');
+  t.regex(headers['x-unleash-sdk'], /^unleash-node@(\d+\.\d+\.\d+)$/);
 });
diff --git a/src/test/unleash.test.ts b/src/test/unleash.test.ts
index 2579cf8b..6f671e96 100644
--- a/src/test/unleash.test.ts
+++ b/src/test/unleash.test.ts
@@ -51,7 +51,10 @@ const defaultToggles = [
 ];
 
 function mockNetwork(toggles = defaultToggles, url = getUrl()) {
-  nock(url).get('/client/features').reply(200, { features: toggles });
+  nock(url)
+    .get('/client/features')
+    .matchHeader('x-unleash-connection-id', /^.{36}$/)
+    .reply(200, { features: toggles });
   return url;
 }
 
diff --git a/src/unleash.ts b/src/unleash.ts
index 81c24907..588a06a8 100644
--- a/src/unleash.ts
+++ b/src/unleash.ts
@@ -22,6 +22,7 @@ import { resolveUrl } from './url-utils';
 // @ts-expect-error
 import { EventSource } from 'launchdarkly-eventsource';
 import { buildHeaders } from './request';
+import { randomUUID } from 'crypto';
 export { Strategy, UnleashEvents, UnleashConfig };
 
 const BACKUP_PATH: string = tmpdir();
@@ -107,6 +108,8 @@ export class Unleash extends EventEmitter {
 
     const unleashInstanceId = generateInstanceId(instanceId);
 
+    const unleashConnectionId = randomUUID();
+
     this.staticContext = { appName, environment };
 
     const bootstrapProvider = resolveBootstrapProvider(bootstrap, appName, unleashInstanceId);
@@ -118,6 +121,7 @@ export class Unleash extends EventEmitter {
         url: unleashUrl,
         appName,
         instanceId: unleashInstanceId,
+        connectionId: unleashConnectionId,
         refreshInterval,
         headers: customHeaders,
         customHeadersFunction,
@@ -130,14 +134,15 @@ export class Unleash extends EventEmitter {
         eventSource:
           experimentalMode?.type === 'streaming'
             ? new EventSource(resolveUrl(unleashUrl, './client/streaming'), {
-                headers: buildHeaders(
+                headers: buildHeaders({
                   appName,
-                  instanceId,
-                  undefined,
-                  undefined,
-                  customHeaders,
-                  SUPPORTED_SPEC_VERSION,
-                ),
+                  instanceId: unleashInstanceId,
+                  etag: undefined,
+                  contentType: undefined,
+                  custom: customHeaders,
+                  specVersionSupported: SUPPORTED_SPEC_VERSION,
+                  connectionId: unleashConnectionId,
+                }),
                 readTimeoutMillis: 60000, // start a new SSE connection when no heartbeat received in 1 minute
                 initialRetryDelayMillis: 2000,
                 maxBackoffMillis: 30000,
@@ -191,6 +196,7 @@ export class Unleash extends EventEmitter {
       disableMetrics,
       appName,
       instanceId: unleashInstanceId,
+      connectionId: unleashConnectionId,
       strategies: supportedStrategies.map((strategy: Strategy) => strategy.name),
       metricsInterval,
       metricsJitter,