diff --git a/README.md b/README.md
index 45a5f5d..2995d89 100644
--- a/README.md
+++ b/README.md
@@ -2,10 +2,10 @@
 A wrapper in Node for the compiled protoc from https://github.com/protocolbuffers/protobuf.
 
 ## Version
-It's currently using Protocol Buffers `v3.20.3`.
+It's currently using Protocol Buffers `v21.9`.
 
 ## Platforms
-Google only provides binary files for Windows, Linux and OSX in x86_64 and x86_32.
+Google only provides binary files for Windows, Linux and macOS in aarch64, x86_64 and x86_32.
 
 ## Examples
 There's currently no documentation. Hopefully this example will help.
diff --git a/index.js b/index.js
index 1daed70..8e27509 100644
--- a/index.js
+++ b/index.js
@@ -52,7 +52,7 @@ exports.closure = function(files, options, callback) {
  * Converts .proto files to .js files that can be used in Google Closure
  * Compiler.
  * The generated .js files require the files in
- * https://github.com/protocolbuffers/protobuf/tree/v3.20.3/js.
+ * https://github.com/protocolbuffers/protobuf-javascript.
  * @param {?Array<string>} files the proto files.
  * @param {?function(?Error, ?Array<Vinyl>)} callback the callback method.
  */
diff --git a/scripts/postinstall.js b/scripts/postinstall.js
index a606585..4991490 100644
--- a/scripts/postinstall.js
+++ b/scripts/postinstall.js
@@ -4,18 +4,24 @@ const unzip = require("unzipper");
 const mkdirp = require("mkdirp");
 const protoc = require("../protoc.js");
 
-const protoVersion = "3.20.3";
+const protoVersion = "21.9";
 
 const releases = {
   "win32_x86_32": `https://github.com/protocolbuffers/protobuf/releases/download/v${protoVersion}/protoc-${protoVersion}-win32.zip`,
   "win32_x86_64": `https://github.com/protocolbuffers/protobuf/releases/download/v${protoVersion}/protoc-${protoVersion}-win32.zip`,
   "linux_x86_32": `https://github.com/protocolbuffers/protobuf/releases/download/v${protoVersion}/protoc-${protoVersion}-linux-x86_32.zip`,
   "linux_x86_64": `https://github.com/protocolbuffers/protobuf/releases/download/v${protoVersion}/protoc-${protoVersion}-linux-x86_64.zip`,
-  "darwin_x86_64": `https://github.com/protocolbuffers/protobuf/releases/download/v${protoVersion}/protoc-${protoVersion}-osx-x86_64.zip`
+  "darwin_x86_64": `https://github.com/protocolbuffers/protobuf/releases/download/v${protoVersion}/protoc-${protoVersion}-osx-x86_64.zip`,
+  "darwin_arm64": `https://github.com/protocolbuffers/protobuf/releases/download/v${protoVersion}/protoc-${protoVersion}-osx-aarch_64.zip`
 };
 
 const platform = process.platform;
-const arch = process.arch === "x64" ? "x86_64" : "x86_32";
+const arch =
+  process.arch === "arm64"
+    ? "arm64"
+    : process.arch === "x64"
+    ? "x86_64"
+    : "x86_32";
 const release = platform + "_" + arch;
 const protocDirectory = path.join(__dirname, "..", "protoc");