diff --git a/CHANGES.md b/CHANGES.md
index 6aac36d3..3f168bc0 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -11,6 +11,15 @@
 
 ## develop
 
+## 2024.1.2
+
+**2024-07-09**
+
+- [FIX] `"type": "offer"` の `simulcast` の値が反映されていない問題を修正する
+  - @voluntas
+- [FIX] `"type": "offer"` の `bundle_id` と `spotlight` を保持するように修正する
+  - @voluntas
+
 ## 2024.1.1
 
 **2024-06-17**
diff --git a/package.json b/package.json
index 837fabe8..4e6380a6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "sora-js-sdk",
-  "version": "2024.1.1",
+  "version": "2024.1.2",
   "description": "WebRTC SFU Sora JavaScript SDK",
   "main": "dist/sora.js",
   "module": "dist/sora.mjs",
diff --git a/packages/sdk/src/base.ts b/packages/sdk/src/base.ts
index f916c467..8604c9e1 100644
--- a/packages/sdk/src/base.ts
+++ b/packages/sdk/src/base.ts
@@ -62,6 +62,14 @@ export default class ConnectionBase {
    * ロール(sendonly | sendrecv | recvonly)
    */
   role: string
+  /**
+   * サイマルキャスト
+   */
+  simulcast: boolean
+  /**
+   * スポットライト
+   */
+  spotlight: boolean
   /**
    * チャネルID
    */
@@ -87,6 +95,10 @@ export default class ConnectionBase {
    * デバッグフラグ
    */
   debug: boolean
+  /**
+   * バンドルID
+   */
+  bundleId: string | null
   /**
    * クライアントID
    */
@@ -229,9 +241,12 @@ export default class ConnectionBase {
     }
     this.constraints = null
     this.debug = debug
+    this.simulcast = false
+    this.spotlight = false
+    this.sessionId = null
     this.clientId = null
+    this.bundleId = null
     this.connectionId = null
-    this.sessionId = null
     this.remoteConnectionIds = []
     this.stream = null
     this.ws = null
@@ -723,9 +738,14 @@ export default class ConnectionBase {
    * 接続状態の初期化をするメソッド
    */
   private initializeConnection(): void {
+    this.simulcast = false
+    this.spotlight = false
+
+    this.sessionId = null
     this.clientId = null
+    this.bundleId = null
     this.connectionId = null
-    this.sessionId = null
+
     this.remoteConnectionIds = []
     this.stream = null
     this.ws = null
@@ -1391,7 +1411,7 @@ export default class ConnectionBase {
       }
     }
     // simulcast の場合
-    if (this.options.simulcast && (this.role === 'sendrecv' || this.role === 'sendonly')) {
+    if (this.simulcast && (this.role === 'sendrecv' || this.role === 'sendonly')) {
       const transceiver = this.pc.getTransceivers().find((t) => {
         if (t.mid === null) {
           return
@@ -1878,11 +1898,17 @@ export default class ConnectionBase {
    * @param message - type offer メッセージ
    */
   private signalingOnMessageTypeOffer(message: SignalingOfferMessage): void {
-    this.clientId = message.client_id
-    this.connectionId = message.connection_id
+    this.simulcast = message.simulcast
+    this.spotlight = message.spotlight
+
+    // 互換性を考慮してオプションとする
     if (message.session_id !== undefined) {
       this.sessionId = message.session_id
     }
+    this.clientId = message.client_id
+    this.bundleId = message.bundle_id
+    this.connectionId = message.connection_id
+
     if (message.metadata !== undefined) {
       this.authMetadata = message.metadata
     }
diff --git a/packages/sdk/src/types.ts b/packages/sdk/src/types.ts
index 292c3e99..fbe8c264 100644
--- a/packages/sdk/src/types.ts
+++ b/packages/sdk/src/types.ts
@@ -105,10 +105,19 @@ export type SignalingOfferMessageDataChannel = {
 export type SignalingOfferMessage = {
   type: 'offer'
   sdp: string
+
+  multistream: boolean
+  simulcast: boolean
+  simulcast_multicodec: boolean
+  spotlight: boolean
+
+  channel_id: string
+  // 互換性を考慮してオプションとする
+  session_id?: string
   client_id: string
+  bundle_id: string
   connection_id: string
-  session_id?: string
-  bundle_id?: string
+
   metadata?: JSONType
   config?: RTCConfiguration
   encodings?: RTCRtpEncodingParameters[]