diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9898af4..3236f35 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,15 @@
 # Changelog
 
+## [4.2.0] - 2024-01-11
+
+### Added
+
+- Add `content_safety_confidence` to `TranscriptParams` & `TranscriptOptionalParams`.
+
+### Changed
+
+- The `RealtimeService` now sends audio as binary instead of a base64-encoded JSON object.
+
 ## [4.1.0] - 2023-12-22
 
 ### Added
diff --git a/package.json b/package.json
index dfde867..787dc27 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "assemblyai",
-  "version": "4.1.0",
+  "version": "4.2.0",
   "description": "The AssemblyAI JavaScript SDK provides an easy-to-use interface for interacting with the AssemblyAI API, which supports async and real-time transcription, as well as the latest LeMUR models.",
   "engines": {
     "node": ">=18"
diff --git a/src/services/realtime/service.ts b/src/services/realtime/service.ts
index 2b76a7e..8ab2235 100644
--- a/src/services/realtime/service.ts
+++ b/src/services/realtime/service.ts
@@ -102,6 +102,7 @@ export class RealtimeService {
           headers: { Authorization: this.apiKey },
         });
       }
+      this.socket.binaryType = "arraybuffer";
 
       this.socket.onclose = ({ code, reason }: CloseEvent) => {
         if (!reason) {
@@ -160,23 +161,7 @@ export class RealtimeService {
     if (!this.socket || this.socket.readyState !== WebSocket.OPEN) {
       throw new Error("Socket is not open for communication");
     }
-    let audioData;
-    if (typeof Buffer !== "undefined") {
-      audioData = Buffer.from(audio).toString("base64");
-    } else {
-      // Buffer is not available in the browser by default
-      // https://stackoverflow.com/a/42334410/2919731
-      audioData = btoa(
-        new Uint8Array(audio).reduce(
-          (data, byte) => data + String.fromCharCode(byte),
-          ""
-        )
-      );
-    }
-    const payload = {
-      audio_data: audioData,
-    };
-    this.socket.send(JSON.stringify(payload));
+    this.socket.send(audio);
   }
 
   stream(): WritableStream<ArrayBufferLike> {
diff --git a/src/types/openapi.generated.ts b/src/types/openapi.generated.ts
index b318d7a..f68cc6b 100644
--- a/src/types/openapi.generated.ts
+++ b/src/types/openapi.generated.ts
@@ -514,6 +514,12 @@ export type LemurBaseParams = {
       }
     ]
   >;
+  /**
+   * @description The model that is used for the final prompt after compression is performed.
+   * Defaults to "default".
+   *
+   * @default default
+   */
   final_model?: LiteralUnion<LemurModel, string>;
   /**
    * @description Custom formatted transcript data. Maximum size is the context limit of the selected model, which defaults to 100000.
@@ -2305,6 +2311,8 @@ export type TranscriptOptionalParams = {
   boost_param?: TranscriptBoostParam;
   /** @description Enable [Content Moderation](https://www.assemblyai.com/docs/models/content-moderation), can be true or false */
   content_safety?: boolean;
+  /** @description The confidence threshold for content moderation. Values must be between 25 and 100. */
+  content_safety_confidence?: number;
   /** @description Customize how words are spelled and formatted using to and from values */
   custom_spelling?: TranscriptCustomSpelling[];
   /** @description Whether custom topics is enabled, either true or false */
diff --git a/tests/realtime.test.ts b/tests/realtime.test.ts
index 034b44e..84fe72c 100644
--- a/tests/realtime.test.ts
+++ b/tests/realtime.test.ts
@@ -136,9 +136,7 @@ describe("realtime", () => {
   it("can send audio", async () => {
     const data = new ArrayBuffer(8);
     rt.sendAudio(data);
-    await expect(server).toReceiveMessage(
-      JSON.stringify({ audio_data: Buffer.from(data).toString("base64") })
-    );
+    await expect(server).toReceiveMessage(data);
   });
 
   it("can send audio using stream", async () => {
@@ -146,10 +144,9 @@ describe("realtime", () => {
     const writer = stream.writable.getWriter();
     stream.readable.pipeTo(rt.stream());
     await writer.ready;
-    writer.write(Buffer.alloc(5_000));
-    await expect(server).toReceiveMessage(
-      JSON.stringify({ audio_data: Buffer.alloc(5_000).toString("base64") })
-    );
+    const data = Buffer.alloc(5_000);
+    writer.write(data);
+    await expect(server).toReceiveMessage(data);
   });
 
   it("can receive transcript", () => {