diff --git a/addons/xterm-addon-attach/src/AttachAddon.api.ts b/addons/xterm-addon-attach/src/AttachAddon.api.ts
index 945824a2..c5b2d858 100644
--- a/addons/xterm-addon-attach/src/AttachAddon.api.ts
+++ b/addons/xterm-addon-attach/src/AttachAddon.api.ts
@@ -54,7 +54,7 @@ describe('AttachAddon', () => {
     const server = new WebSocket.Server({ port });
     const data = new Uint8Array([102, 111, 111]);
     server.on('connection', socket => socket.send(data));
-    await page.evaluate(`window.term.loadAddon(new window.AttachAddon(new WebSocket('ws://localhost:${port}'), { inputUtf8: true }))`);
+    await page.evaluate(`window.term.loadAddon(new window.AttachAddon(new WebSocket('ws://localhost:${port}')))`);
     assert.equal(await page.evaluate(`window.term.buffer.getLine(0).translateToString(true)`), 'foo');
     server.close();
   });
diff --git a/addons/xterm-addon-attach/src/AttachAddon.ts b/addons/xterm-addon-attach/src/AttachAddon.ts
index 9dc45ecb..d0bbce16 100644
--- a/addons/xterm-addon-attach/src/AttachAddon.ts
+++ b/addons/xterm-addon-attach/src/AttachAddon.ts
@@ -9,13 +9,11 @@ import { Terminal, IDisposable, ITerminalAddon } from 'xterm';
 
 interface IAttachOptions {
   bidirectional?: boolean;
-  inputUtf8?: boolean;
 }
 
 export class AttachAddon implements ITerminalAddon {
   private _socket: WebSocket;
   private _bidirectional: boolean;
-  private _utf8: boolean;
   private _disposables: IDisposable[] = [];
 
   constructor(socket: WebSocket, options?: IAttachOptions) {
@@ -23,17 +21,17 @@ export class AttachAddon implements ITerminalAddon {
     // always set binary type to arraybuffer, we do not handle blobs
     this._socket.binaryType = 'arraybuffer';
     this._bidirectional = (options && options.bidirectional === false) ? false : true;
-    this._utf8 = !!(options && options.inputUtf8);
   }
 
   public activate(terminal: Terminal): void {
-    if (this._utf8) {
-      this._disposables.push(addSocketListener(this._socket, 'message',
-        (ev: MessageEvent | Event | CloseEvent) => terminal.writeUtf8(new Uint8Array((ev as any).data as ArrayBuffer))));
-    } else {
-      this._disposables.push(addSocketListener(this._socket, 'message',
-        (ev: MessageEvent | Event | CloseEvent) => terminal.write((ev as any).data as string)));
-    }
+    this._disposables.push(
+      addSocketListener(this._socket, 'message',
+        (ev: MessageEvent | Event | CloseEvent) => {
+          const data: ArrayBuffer | string = (ev as any).data;
+          terminal.write(typeof data === 'string' ? data : new Uint8Array(data));
+        }
+      )
+    );
 
     if (this._bidirectional) {
       this._disposables.push(terminal.onData(data => this._sendData(data)));
diff --git a/addons/xterm-addon-attach/typings/xterm-addon-attach.d.ts b/addons/xterm-addon-attach/typings/xterm-addon-attach.d.ts
index 8c667140..1aa21357 100644
--- a/addons/xterm-addon-attach/typings/xterm-addon-attach.d.ts
+++ b/addons/xterm-addon-attach/typings/xterm-addon-attach.d.ts
@@ -11,14 +11,6 @@ declare module 'xterm-addon-attach' {
      * Whether input should be written to the backend. Defaults to `true`.
      */
     bidirectional?: boolean;
-
-    /**
-     * Whether to use UTF8 binary transport for incoming messages. Defaults to `false`.
-     * Note: This must be in line with the server side of the websocket.
-     *       Always send string messages from the backend if this options is false,
-     *       otherwise always binary UTF8 data.
-     */
-    inputUtf8?: boolean;
   }
 
   export class AttachAddon implements ITerminalAddon {
diff --git a/demo/client.ts b/demo/client.ts
index 040292e4..92bac731 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -167,14 +167,7 @@ function createTerminal(): void {
 }
 
 function runRealTerminal(): void {
-  /**
-   * The demo defaults to string transport by default.
-   * To run it with UTF8 binary transport, swap comment on
-   * the lines below. (Must also be switched in server.js)
-   */
   term.loadAddon(new AttachAddon(socket));
-  // term.loadAddon(new AttachAddon(socket, {inputUtf8: true}));
-
   term._initialized = true;
 }
 
diff --git a/demo/server.js b/demo/server.js
index f1fae572..a2987558 100644
--- a/demo/server.js
+++ b/demo/server.js
@@ -4,10 +4,9 @@ var os = require('os');
 var pty = require('node-pty');
 
 /**
- * Whether to use UTF8 binary transport.
- * (Must also be switched in client.ts)
+ * Whether to use binary transport.
  */
-const USE_BINARY_UTF8 = false;
+const USE_BINARY = true;
 
 
 function startServer() {
@@ -46,7 +45,7 @@ function startServer() {
           rows: rows || 24,
           cwd: env.PWD,
           env: env,
-          encoding: USE_BINARY_UTF8 ? null : 'utf8'
+          encoding: USE_BINARY ? null : 'utf8'
         });
 
     console.log('Created terminal with PID: ' + term.pid);
@@ -108,7 +107,7 @@ function startServer() {
         }
       };
     }
-    const send = USE_BINARY_UTF8 ? bufferUtf8(ws, 5) : buffer(ws, 5);
+    const send = USE_BINARY ? bufferUtf8(ws, 5) : buffer(ws, 5);
 
     term.on('data', function(data) {
       try {
diff --git a/src/Terminal.ts b/src/Terminal.ts
index f95873b8..53d8fe3c 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -1597,7 +1597,7 @@ export class Terminal extends Disposable implements ITerminal, IDisposable, IInp
   public write(data: string | Uint8Array, callback?: () => void): void {
     this._writeBuffer.write(data, callback);
   }
-  
+
   public writeSync(data: string | Uint8Array): void {
     this._writeBuffer.writeSync(data);
   }