diff --git a/lib/manager.ts b/lib/manager.ts
index bace6061d..b4c7f1bfa 100644
--- a/lib/manager.ts
+++ b/lib/manager.ts
@@ -5,7 +5,6 @@ import * as parser from "socket.io-parser";
 import { Decoder, Encoder } from "socket.io-parser";
 import { on } from "./on";
 import * as bind from "component-bind";
-import * as indexOf from "indexof";
 import * as Backoff from "backo2";
 
 const debug = require("debug")("socket.io-client:manager");
@@ -595,7 +594,7 @@ export class Manager extends Emitter {
     }
 
     function onConnecting() {
-      if (!~indexOf(self.connecting, socket)) {
+      if (!~self.connecting.indexOf(socket)) {
         self.connecting.push(socket);
       }
     }
@@ -610,7 +609,7 @@ export class Manager extends Emitter {
    * @private
    */
   _destroy(socket) {
-    const index = indexOf(this.connecting, socket);
+    const index = this.connecting.indexOf(socket);
     if (~index) this.connecting.splice(index, 1);
     if (this.connecting.length) return;
 
diff --git a/lib/socket.ts b/lib/socket.ts
index 75c748c86..c79b86152 100644
--- a/lib/socket.ts
+++ b/lib/socket.ts
@@ -2,7 +2,6 @@ import { Packet, PacketType } from "socket.io-parser";
 import * as Emitter from "component-emitter";
 import { on } from "./on";
 import * as bind from "component-bind";
-import * as hasBin from "has-binary2";
 import { Manager } from "./manager";
 
 const debug = require("debug")("socket.io-client:socket");
@@ -132,9 +131,7 @@ export class Socket extends Emitter {
 
     args.unshift(ev);
     const packet: any = {
-      type: (this.flags.binary !== undefined ? this.flags.binary : hasBin(args))
-        ? PacketType.BINARY_EVENT
-        : PacketType.EVENT,
+      type: PacketType.EVENT,
       data: args,
     };
 
@@ -282,7 +279,7 @@ export class Socket extends Emitter {
       debug("sending ack %j", args);
 
       self.packet({
-        type: hasBin(args) ? PacketType.BINARY_ACK : PacketType.ACK,
+        type: PacketType.ACK,
         id: id,
         data: args,
       });
@@ -409,16 +406,4 @@ export class Socket extends Emitter {
     this.flags.compress = compress;
     return this;
   }
-
-  /**
-   * Sets the binary flag
-   *
-   * @param {Boolean} binary - whether the emitted data contains binary
-   * @return {Socket} self
-   * @public
-   */
-  public binary(binary: boolean): Socket {
-    this.flags.binary = binary;
-    return this;
-  }
 }
diff --git a/package.json b/package.json
index ea861dc97..c3e653e3d 100644
--- a/package.json
+++ b/package.json
@@ -33,10 +33,8 @@
     "component-emitter": "~1.3.0",
     "debug": "~4.1.0",
     "engine.io-client": "~4.0.0",
-    "has-binary2": "~1.0.2",
-    "indexof": "0.0.1",
     "parseuri": "0.0.6",
-    "socket.io-parser": "4.0.1-rc1"
+    "socket.io-parser": "4.0.1-rc2"
   },
   "devDependencies": {
     "@babel/core": "^7.11.6",
diff --git a/tsconfig.json b/tsconfig.json
index bd40c1107..8cd92f0d6 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -4,8 +4,7 @@
     "allowJs": false,
     "target": "es2017",
     "module": "commonjs",
-    "declaration": true,
-    "allowSyntheticDefaultImports": true
+    "declaration": true
   },
   "include": [
     "./lib/**/*"