diff --git a/browser/wsproxy.js b/browser/wsproxy.js
index 2588b448..5fce0994 100644
--- a/browser/wsproxy.js
+++ b/browser/wsproxy.js
@@ -39,7 +39,7 @@ function WSProxy(options) {
   this.init();
 }
 
-util.inherits(WSProxy, EventEmitter);
+Object.setPrototypeOf(WSProxy.prototype, EventEmitter.prototype);
 
 WSProxy.prototype.init = function init() {
   this.io.on('error', (err) => {
diff --git a/lib/blockchain/chain.js b/lib/blockchain/chain.js
index 56ca0bcb..4610fabd 100644
--- a/lib/blockchain/chain.js
+++ b/lib/blockchain/chain.js
@@ -86,7 +86,7 @@ function Chain(options) {
   this.db = new ChainDB(this);
 }
 
-util.inherits(Chain, AsyncObject);
+Object.setPrototypeOf(Chain.prototype, AsyncObject.prototype);
 
 /**
  * Open the chain, wait for the database to load.
diff --git a/lib/http/base.js b/lib/http/base.js
index a1dd0e9a..3af24188 100644
--- a/lib/http/base.js
+++ b/lib/http/base.js
@@ -50,7 +50,7 @@ function HTTPBase(options) {
   this._init();
 }
 
-util.inherits(HTTPBase, AsyncObject);
+Object.setPrototypeOf(HTTPBase.prototype, AsyncObject.prototype);
 
 /**
  * Initialize server.
@@ -1218,7 +1218,7 @@ function Request(req, res, url) {
     this.init(req, res, url);
 }
 
-util.inherits(Request, EventEmitter);
+Object.setPrototypeOf(Request.prototype, EventEmitter.prototype);
 
 Request.prototype.init = function init(req, res, url) {
   assert(req);
@@ -1369,7 +1369,7 @@ function Response(req, res) {
     this.init(req, res);
 }
 
-util.inherits(Response, EventEmitter);
+Object.setPrototypeOf(Response.prototype, EventEmitter.prototype);
 
 Response.prototype.init = function init(req, res) {
   assert(req);
@@ -1535,7 +1535,7 @@ function WebSocket(socket, ctx) {
   this.init();
 }
 
-util.inherits(WebSocket, EventEmitter);
+Object.setPrototypeOf(WebSocket.prototype, EventEmitter.prototype);
 
 WebSocket.prototype.init = function init() {
   const socket = this.socket;
diff --git a/lib/http/client.js b/lib/http/client.js
index 48e1e935..6d7c6d15 100644
--- a/lib/http/client.js
+++ b/lib/http/client.js
@@ -10,7 +10,6 @@
 const Network = require('../protocol/network');
 const AsyncObject = require('../utils/asyncobject');
 const RPCClient = require('./rpcclient');
-const util = require('../utils/util');
 const request = require('./request');
 
 /**
@@ -43,7 +42,7 @@ function HTTPClient(options) {
   this.rpc = new RPCClient(options);
 }
 
-util.inherits(HTTPClient, AsyncObject);
+Object.setPrototypeOf(HTTPClient.prototype, AsyncObject.prototype);
 
 /**
  * Open the client, wait for socket to connect.
diff --git a/lib/http/rpc.js b/lib/http/rpc.js
index e133c5cd..a146fb34 100644
--- a/lib/http/rpc.js
+++ b/lib/http/rpc.js
@@ -75,7 +75,7 @@ function RPC(node) {
   this.init();
 }
 
-util.inherits(RPC, RPCBase);
+Object.setPrototypeOf(RPC.prototype, RPCBase.prototype);
 
 RPC.prototype.init = function init() {
   this.add('stop', this.stop);
diff --git a/lib/http/rpcbase.js b/lib/http/rpcbase.js
index 987924b5..038c1550 100644
--- a/lib/http/rpcbase.js
+++ b/lib/http/rpcbase.js
@@ -8,7 +8,6 @@
 
 const assert = require('assert');
 const EventEmitter = require('events');
-const util = require('../utils/util');
 const Lock = require('../utils/lock');
 const Logger = require('../node/logger');
 
@@ -30,7 +29,7 @@ function RPCBase() {
   this.locker = new Lock();
 }
 
-util.inherits(RPCBase, EventEmitter);
+Object.setPrototypeOf(RPCBase.prototype, EventEmitter.prototype);
 
 /**
  * RPC errors.
@@ -312,7 +311,7 @@ function RPCError(code, msg) {
     Error.captureStackTrace(this, RPCError);
 }
 
-util.inherits(RPCError, Error);
+Object.setPrototypeOf(RPCError.prototype, Error.prototype);
 
 /*
  * Expose
diff --git a/lib/http/rpcclient.js b/lib/http/rpcclient.js
index 75e869e6..c8a498bd 100644
--- a/lib/http/rpcclient.js
+++ b/lib/http/rpcclient.js
@@ -8,7 +8,6 @@
 
 const Network = require('../protocol/network');
 const request = require('./request');
-const util = require('../utils/util');
 
 /**
  * Bcoin RPC client.
@@ -93,7 +92,7 @@ function RPCError(msg, code) {
     Error.captureStackTrace(this, RPCError);
 }
 
-util.inherits(RPCError, Error);
+Object.setPrototypeOf(RPCError.prototype, Error.prototype);
 
 /*
  * Expose
diff --git a/lib/http/server.js b/lib/http/server.js
index a68cf252..e21b855a 100644
--- a/lib/http/server.js
+++ b/lib/http/server.js
@@ -55,7 +55,7 @@ function HTTPServer(options) {
   this.init();
 }
 
-util.inherits(HTTPServer, HTTPBase);
+Object.setPrototypeOf(HTTPServer.prototype, HTTPBase.prototype);
 
 /**
  * Initialize routes.
diff --git a/lib/http/wallet.js b/lib/http/wallet.js
index a79847c1..8111ff99 100644
--- a/lib/http/wallet.js
+++ b/lib/http/wallet.js
@@ -10,7 +10,6 @@
 const assert = require('assert');
 const EventEmitter = require('events');
 const Network = require('../protocol/network');
-const util = require('../utils/util');
 const Client = require('./client');
 
 /**
@@ -53,7 +52,7 @@ function HTTPWallet(options) {
   this._init();
 }
 
-util.inherits(HTTPWallet, EventEmitter);
+Object.setPrototypeOf(HTTPWallet.prototype, EventEmitter.prototype);
 
 /**
  * Initialize the wallet.
diff --git a/lib/mempool/mempool.js b/lib/mempool/mempool.js
index 7c7c9ff2..e7ce9b49 100644
--- a/lib/mempool/mempool.js
+++ b/lib/mempool/mempool.js
@@ -95,7 +95,7 @@ function Mempool(options) {
   this.txIndex = new TXIndex();
 }
 
-util.inherits(Mempool, AsyncObject);
+Object.setPrototypeOf(Mempool.prototype, AsyncObject.prototype);
 
 /**
  * Open the chain, wait for the database to load.
diff --git a/lib/mining/cpuminer.js b/lib/mining/cpuminer.js
index 0ea901eb..6bb7cda5 100644
--- a/lib/mining/cpuminer.js
+++ b/lib/mining/cpuminer.js
@@ -44,7 +44,7 @@ function CPUMiner(miner) {
   this._init();
 }
 
-util.inherits(CPUMiner, AsyncObject);
+Object.setPrototypeOf(CPUMiner.prototype, AsyncObject.prototype);
 
 /**
  * Nonce range interval.
diff --git a/lib/mining/miner.js b/lib/mining/miner.js
index 21c680a1..6b19a254 100644
--- a/lib/mining/miner.js
+++ b/lib/mining/miner.js
@@ -46,7 +46,7 @@ function Miner(options) {
   this.init();
 }
 
-util.inherits(Miner, AsyncObject);
+Object.setPrototypeOf(Miner.prototype, AsyncObject.prototype);
 
 /**
  * Open the miner, wait for the chain and mempool to load.
diff --git a/lib/net/bip150.js b/lib/net/bip150.js
index 36206165..1251ddb4 100644
--- a/lib/net/bip150.js
+++ b/lib/net/bip150.js
@@ -11,7 +11,6 @@
 const assert = require('assert');
 const path = require('path');
 const EventEmitter = require('events');
-const util = require('../utils/util');
 const co = require('../utils/co');
 const digest = require('../crypto/digest');
 const random = require('../crypto/random');
@@ -87,7 +86,7 @@ function BIP150(bip151, host, outbound, db, key) {
   this._init();
 }
 
-util.inherits(BIP150, EventEmitter);
+Object.setPrototypeOf(BIP150.prototype, EventEmitter.prototype);
 
 /**
  * Initialize BIP150.
diff --git a/lib/net/bip151.js b/lib/net/bip151.js
index 50938f1b..cdfa2020 100644
--- a/lib/net/bip151.js
+++ b/lib/net/bip151.js
@@ -329,7 +329,7 @@ function BIP151(cipher) {
   this.bip150 = null;
 }
 
-util.inherits(BIP151, EventEmitter);
+Object.setPrototypeOf(BIP151.prototype, EventEmitter.prototype);
 
 /**
  * Cipher list.
diff --git a/lib/net/bip152.js b/lib/net/bip152.js
index f2e44d72..28e42f28 100644
--- a/lib/net/bip152.js
+++ b/lib/net/bip152.js
@@ -59,7 +59,7 @@ function CompactBlock(options) {
     this.fromOptions(options);
 }
 
-util.inherits(CompactBlock, AbstractBlock);
+Object.setPrototypeOf(CompactBlock.prototype, AbstractBlock.prototype);
 
 /**
  * Inject properties from options object.
diff --git a/lib/net/packets.js b/lib/net/packets.js
index de225b70..c1702512 100644
--- a/lib/net/packets.js
+++ b/lib/net/packets.js
@@ -180,7 +180,7 @@ function VersionPacket(options) {
     this.fromOptions(options);
 }
 
-util.inherits(VersionPacket, Packet);
+Object.setPrototypeOf(VersionPacket.prototype, Packet.prototype);
 
 VersionPacket.prototype.cmd = 'version';
 VersionPacket.prototype.type = exports.types.VERSION;
@@ -366,7 +366,7 @@ function VerackPacket() {
   Packet.call(this);
 }
 
-util.inherits(VerackPacket, Packet);
+Object.setPrototypeOf(VerackPacket.prototype, Packet.prototype);
 
 VerackPacket.prototype.cmd = 'verack';
 VerackPacket.prototype.type = exports.types.VERACK;
@@ -410,7 +410,7 @@ function PingPacket(nonce) {
   this.nonce = nonce || null;
 }
 
-util.inherits(PingPacket, Packet);
+Object.setPrototypeOf(PingPacket.prototype, Packet.prototype);
 
 PingPacket.prototype.cmd = 'ping';
 PingPacket.prototype.type = exports.types.PING;
@@ -506,7 +506,7 @@ function PongPacket(nonce) {
   this.nonce = nonce || encoding.ZERO_U64;
 }
 
-util.inherits(PongPacket, Packet);
+Object.setPrototypeOf(PongPacket.prototype, Packet.prototype);
 
 PongPacket.prototype.cmd = 'pong';
 PongPacket.prototype.type = exports.types.PONG;
@@ -595,7 +595,7 @@ function GetAddrPacket() {
   Packet.call(this);
 }
 
-util.inherits(GetAddrPacket, Packet);
+Object.setPrototypeOf(GetAddrPacket.prototype, Packet.prototype);
 
 GetAddrPacket.prototype.cmd = 'getaddr';
 GetAddrPacket.prototype.type = exports.types.GETADDR;
@@ -639,7 +639,7 @@ function AddrPacket(items) {
   this.items = items || [];
 }
 
-util.inherits(AddrPacket, Packet);
+Object.setPrototypeOf(AddrPacket.prototype, Packet.prototype);
 
 AddrPacket.prototype.cmd = 'addr';
 AddrPacket.prototype.type = exports.types.ADDR;
@@ -735,7 +735,7 @@ function InvPacket(items) {
   this.items = items || [];
 }
 
-util.inherits(InvPacket, Packet);
+Object.setPrototypeOf(InvPacket.prototype, Packet.prototype);
 
 InvPacket.prototype.cmd = 'inv';
 InvPacket.prototype.type = exports.types.INV;
@@ -842,7 +842,7 @@ function GetDataPacket(items) {
   InvPacket.call(this, items);
 }
 
-util.inherits(GetDataPacket, InvPacket);
+Object.setPrototypeOf(GetDataPacket.prototype, InvPacket.prototype);
 
 GetDataPacket.prototype.cmd = 'getdata';
 GetDataPacket.prototype.type = exports.types.GETDATA;
@@ -884,7 +884,7 @@ function NotFoundPacket(items) {
   InvPacket.call(this, items);
 }
 
-util.inherits(NotFoundPacket, InvPacket);
+Object.setPrototypeOf(NotFoundPacket.prototype, InvPacket.prototype);
 
 NotFoundPacket.prototype.cmd = 'notfound';
 NotFoundPacket.prototype.type = exports.types.NOTFOUND;
@@ -932,7 +932,7 @@ function GetBlocksPacket(locator, stop) {
   this.stop = stop || null;
 }
 
-util.inherits(GetBlocksPacket, Packet);
+Object.setPrototypeOf(GetBlocksPacket.prototype, Packet.prototype);
 
 GetBlocksPacket.prototype.cmd = 'getblocks';
 GetBlocksPacket.prototype.type = exports.types.GETBLOCKS;
@@ -1042,7 +1042,7 @@ function GetHeadersPacket(locator, stop) {
   GetBlocksPacket.call(this, locator, stop);
 }
 
-util.inherits(GetHeadersPacket, GetBlocksPacket);
+Object.setPrototypeOf(GetHeadersPacket.prototype, GetBlocksPacket.prototype);
 
 GetHeadersPacket.prototype.cmd = 'getheaders';
 GetHeadersPacket.prototype.type = exports.types.GETHEADERS;
@@ -1086,7 +1086,7 @@ function HeadersPacket(items) {
   this.items = items || [];
 }
 
-util.inherits(HeadersPacket, Packet);
+Object.setPrototypeOf(HeadersPacket.prototype, Packet.prototype);
 
 HeadersPacket.prototype.cmd = 'headers';
 HeadersPacket.prototype.type = exports.types.HEADERS;
@@ -1185,7 +1185,7 @@ function SendHeadersPacket() {
   Packet.call(this);
 }
 
-util.inherits(SendHeadersPacket, Packet);
+Object.setPrototypeOf(SendHeadersPacket.prototype, Packet.prototype);
 
 SendHeadersPacket.prototype.cmd = 'sendheaders';
 SendHeadersPacket.prototype.type = exports.types.SENDHEADERS;
@@ -1232,7 +1232,7 @@ function BlockPacket(block, witness) {
   this.witness = witness || false;
 }
 
-util.inherits(BlockPacket, Packet);
+Object.setPrototypeOf(BlockPacket.prototype, Packet.prototype);
 
 BlockPacket.prototype.cmd = 'block';
 BlockPacket.prototype.type = exports.types.BLOCK;
@@ -1334,7 +1334,7 @@ function TXPacket(tx, witness) {
   this.witness = witness || false;
 }
 
-util.inherits(TXPacket, Packet);
+Object.setPrototypeOf(TXPacket.prototype, Packet.prototype);
 
 TXPacket.prototype.cmd = 'tx';
 TXPacket.prototype.type = exports.types.TX;
@@ -1442,7 +1442,7 @@ function RejectPacket(options) {
     this.fromOptions(options);
 }
 
-util.inherits(RejectPacket, Packet);
+Object.setPrototypeOf(RejectPacket.prototype, Packet.prototype);
 
 /**
  * Reject codes. Note that `internal` and higher
@@ -1729,7 +1729,7 @@ function MempoolPacket() {
   Packet.call(this);
 }
 
-util.inherits(MempoolPacket, Packet);
+Object.setPrototypeOf(MempoolPacket.prototype, Packet.prototype);
 
 MempoolPacket.prototype.cmd = 'mempool';
 MempoolPacket.prototype.type = exports.types.MEMPOOL;
@@ -1772,7 +1772,7 @@ function FilterLoadPacket(filter) {
   this.filter = filter || new Bloom();
 }
 
-util.inherits(FilterLoadPacket, Packet);
+Object.setPrototypeOf(FilterLoadPacket.prototype, Packet.prototype);
 
 FilterLoadPacket.prototype.cmd = 'filterload';
 FilterLoadPacket.prototype.type = exports.types.FILTERLOAD;
@@ -1874,7 +1874,7 @@ function FilterAddPacket(data) {
   this.data = data || DUMMY;
 }
 
-util.inherits(FilterAddPacket, Packet);
+Object.setPrototypeOf(FilterAddPacket.prototype, Packet.prototype);
 
 FilterAddPacket.prototype.cmd = 'filteradd';
 FilterAddPacket.prototype.type = exports.types.FILTERADD;
@@ -1954,7 +1954,7 @@ function FilterClearPacket() {
   Packet.call(this);
 }
 
-util.inherits(FilterClearPacket, Packet);
+Object.setPrototypeOf(FilterClearPacket.prototype, Packet.prototype);
 
 FilterClearPacket.prototype.cmd = 'filterclear';
 FilterClearPacket.prototype.type = exports.types.FILTERCLEAR;
@@ -1988,7 +1988,7 @@ function MerkleBlockPacket(block) {
   this.block = block || new MerkleBlock();
 }
 
-util.inherits(MerkleBlockPacket, Packet);
+Object.setPrototypeOf(MerkleBlockPacket.prototype, Packet.prototype);
 
 MerkleBlockPacket.prototype.cmd = 'merkleblock';
 MerkleBlockPacket.prototype.type = exports.types.MERKLEBLOCK;
@@ -2071,7 +2071,7 @@ function FeeFilterPacket(rate) {
   this.rate = rate || 0;
 }
 
-util.inherits(FeeFilterPacket, Packet);
+Object.setPrototypeOf(FeeFilterPacket.prototype, Packet.prototype);
 
 FeeFilterPacket.prototype.cmd = 'feefilter';
 FeeFilterPacket.prototype.type = exports.types.FEEFILTER;
@@ -2167,7 +2167,7 @@ function SendCmpctPacket(mode, version) {
   this.version = version || 1;
 }
 
-util.inherits(SendCmpctPacket, Packet);
+Object.setPrototypeOf(SendCmpctPacket.prototype, Packet.prototype);
 
 SendCmpctPacket.prototype.cmd = 'sendcmpct';
 SendCmpctPacket.prototype.type = exports.types.SENDCMPCT;
@@ -2275,7 +2275,7 @@ function CmpctBlockPacket(block, witness) {
   this.witness = witness || false;
 }
 
-util.inherits(CmpctBlockPacket, Packet);
+Object.setPrototypeOf(CmpctBlockPacket.prototype, Packet.prototype);
 
 CmpctBlockPacket.prototype.cmd = 'cmpctblock';
 CmpctBlockPacket.prototype.type = exports.types.CMPCTBLOCK;
@@ -2374,7 +2374,7 @@ function GetBlockTxnPacket(request) {
   this.request = request || new bip152.TXRequest();
 }
 
-util.inherits(GetBlockTxnPacket, Packet);
+Object.setPrototypeOf(GetBlockTxnPacket.prototype, Packet.prototype);
 
 GetBlockTxnPacket.prototype.cmd = 'getblocktxn';
 GetBlockTxnPacket.prototype.type = exports.types.GETBLOCKTXN;
@@ -2470,7 +2470,7 @@ function BlockTxnPacket(response, witness) {
   this.witness = witness || false;
 }
 
-util.inherits(BlockTxnPacket, Packet);
+Object.setPrototypeOf(BlockTxnPacket.prototype, Packet.prototype);
 
 BlockTxnPacket.prototype.cmd = 'blocktxn';
 BlockTxnPacket.prototype.type = exports.types.BLOCKTXN;
@@ -2572,7 +2572,7 @@ function EncinitPacket(publicKey, cipher) {
   this.cipher = cipher || 0;
 }
 
-util.inherits(EncinitPacket, Packet);
+Object.setPrototypeOf(EncinitPacket.prototype, Packet.prototype);
 
 EncinitPacket.prototype.cmd = 'encinit';
 EncinitPacket.prototype.type = exports.types.ENCINIT;
@@ -2667,7 +2667,7 @@ function EncackPacket(publicKey) {
   this.publicKey = publicKey || encoding.ZERO_KEY;
 }
 
-util.inherits(EncackPacket, Packet);
+Object.setPrototypeOf(EncackPacket.prototype, Packet.prototype);
 
 EncackPacket.prototype.cmd = 'encack';
 EncackPacket.prototype.type = exports.types.ENCACK;
@@ -2760,7 +2760,7 @@ function AuthChallengePacket(hash) {
   this.hash = hash || encoding.ZERO_HASH;
 }
 
-util.inherits(AuthChallengePacket, Packet);
+Object.setPrototypeOf(AuthChallengePacket.prototype, Packet.prototype);
 
 AuthChallengePacket.prototype.cmd = 'authchallenge';
 AuthChallengePacket.prototype.type = exports.types.AUTHCHALLENGE;
@@ -2853,7 +2853,7 @@ function AuthReplyPacket(signature) {
   this.signature = signature || encoding.ZERO_SIG64;
 }
 
-util.inherits(AuthReplyPacket, Packet);
+Object.setPrototypeOf(AuthReplyPacket.prototype, Packet.prototype);
 
 AuthReplyPacket.prototype.cmd = 'authreply';
 AuthReplyPacket.prototype.type = exports.types.AUTHREPLY;
@@ -2946,7 +2946,7 @@ function AuthProposePacket(hash) {
   this.hash = hash || encoding.ZERO_HASH;
 }
 
-util.inherits(AuthProposePacket, Packet);
+Object.setPrototypeOf(AuthProposePacket.prototype, Packet.prototype);
 
 AuthProposePacket.prototype.cmd = 'authpropose';
 AuthProposePacket.prototype.type = exports.types.AUTHPROPOSE;
@@ -3042,7 +3042,7 @@ function UnknownPacket(cmd, data) {
   this.data = data;
 }
 
-util.inherits(UnknownPacket, Packet);
+Object.setPrototypeOf(UnknownPacket.prototype, Packet.prototype);
 
 UnknownPacket.prototype.type = exports.types.UNKNOWN;
 
diff --git a/lib/net/parser.js b/lib/net/parser.js
index 96535d58..2a0ddfb5 100644
--- a/lib/net/parser.js
+++ b/lib/net/parser.js
@@ -40,7 +40,7 @@ function Parser(network) {
   this.header = null;
 }
 
-util.inherits(Parser, EventEmitter);
+Object.setPrototypeOf(Parser.prototype, EventEmitter.prototype);
 
 /**
  * Emit an error.
diff --git a/lib/net/peer.js b/lib/net/peer.js
index e719286d..ea4f5055 100644
--- a/lib/net/peer.js
+++ b/lib/net/peer.js
@@ -146,7 +146,7 @@ function Peer(options) {
   this._init();
 }
 
-util.inherits(Peer, EventEmitter);
+Object.setPrototypeOf(Peer.prototype, EventEmitter.prototype);
 
 /**
  * Max output bytes buffered before
diff --git a/lib/net/pool.js b/lib/net/pool.js
index cfd92317..e12f2f55 100644
--- a/lib/net/pool.js
+++ b/lib/net/pool.js
@@ -119,7 +119,7 @@ function Pool(options) {
   this._init();
 };
 
-util.inherits(Pool, AsyncObject);
+Object.setPrototypeOf(Pool.prototype, AsyncObject.prototype);
 
 /**
  * Discovery interval for UPNP and DNS seeds.
@@ -4189,7 +4189,7 @@ function BroadcastItem(pool, msg) {
   this.jobs = [];
 }
 
-util.inherits(BroadcastItem, EventEmitter);
+Object.setPrototypeOf(BroadcastItem.prototype, EventEmitter.prototype);
 
 /**
  * Add a job to be executed on ack, timeout, or reject.
diff --git a/lib/net/proxysocket.js b/lib/net/proxysocket.js
index f6949acd..80f91641 100644
--- a/lib/net/proxysocket.js
+++ b/lib/net/proxysocket.js
@@ -36,7 +36,7 @@ function ProxySocket(uri) {
   this._init();
 }
 
-util.inherits(ProxySocket, EventEmitter);
+Object.setPrototypeOf(ProxySocket.prototype, EventEmitter.prototype);
 
 ProxySocket.prototype._init = function _init() {
   this.socket.on('info', (info) => {
diff --git a/lib/net/socks.js b/lib/net/socks.js
index 2a21b5c7..e0282fa5 100644
--- a/lib/net/socks.js
+++ b/lib/net/socks.js
@@ -42,7 +42,7 @@ function SOCKS() {
   this.proxied = false;
 }
 
-util.inherits(SOCKS, EventEmitter);
+Object.setPrototypeOf(SOCKS.prototype, EventEmitter.prototype);
 
 SOCKS.states = {
   INIT: 0,
@@ -553,7 +553,7 @@ function Proxy(host, port, user, pass) {
   this.ops = [];
 }
 
-util.inherits(Proxy, EventEmitter);
+Object.setPrototypeOf(Proxy.prototype, EventEmitter.prototype);
 
 Proxy.prototype.connect = async function connect(port, host) {
   assert(!this.socket, 'Already connected.');
diff --git a/lib/node/fullnode.js b/lib/node/fullnode.js
index 0ad663a1..7be09415 100644
--- a/lib/node/fullnode.js
+++ b/lib/node/fullnode.js
@@ -7,8 +7,6 @@
 
 'use strict';
 
-const util = require('../utils/util');
-const Node = require('./node');
 const Chain = require('../blockchain/chain');
 const Fees = require('../mempool/fees');
 const Mempool = require('../mempool/mempool');
@@ -16,6 +14,7 @@ const Pool = require('../net/pool');
 const Miner = require('../mining/miner');
 const HTTPServer = require('../http/server');
 const RPC = require('../http/rpc');
+const Node = require('./node');
 
 /**
  * Respresents a fullnode complete with a
@@ -157,7 +156,7 @@ function FullNode(options) {
   this._init();
 }
 
-util.inherits(FullNode, Node);
+Object.setPrototypeOf(FullNode.prototype, Node.prototype);
 
 /**
  * Initialize the node.
diff --git a/lib/node/node.js b/lib/node/node.js
index 9e9d7f86..4615be3e 100644
--- a/lib/node/node.js
+++ b/lib/node/node.js
@@ -59,7 +59,7 @@ function Node(options) {
   this.init();
 }
 
-util.inherits(Node, AsyncObject);
+Object.setPrototypeOf(Node.prototype, AsyncObject.prototype);
 
 /**
  * Initialize options.
diff --git a/lib/node/spvnode.js b/lib/node/spvnode.js
index ab852fba..eb96fc9d 100644
--- a/lib/node/spvnode.js
+++ b/lib/node/spvnode.js
@@ -7,13 +7,12 @@
 
 'use strict';
 
-const util = require('../utils/util');
 const Lock = require('../utils/lock');
-const Node = require('./node');
 const Chain = require('../blockchain/chain');
 const Pool = require('../net/pool');
 const HTTPServer = require('../http/server');
 const RPC = require('../http/rpc');
+const Node = require('./node');
 
 /**
  * Create an spv node which only maintains
@@ -104,7 +103,7 @@ function SPVNode(options) {
   this._init();
 }
 
-util.inherits(SPVNode, Node);
+Object.setPrototypeOf(SPVNode.prototype, Node.prototype);
 
 /**
  * Initialize the node.
diff --git a/lib/primitives/block.js b/lib/primitives/block.js
index 937aec2a..09bda2e2 100644
--- a/lib/primitives/block.js
+++ b/lib/primitives/block.js
@@ -45,7 +45,7 @@ function Block(options) {
     this.fromOptions(options);
 }
 
-util.inherits(Block, AbstractBlock);
+Object.setPrototypeOf(Block.prototype, AbstractBlock.prototype);
 
 /**
  * Inject properties from options object.
diff --git a/lib/primitives/coin.js b/lib/primitives/coin.js
index 6a32d420..f4c5101a 100644
--- a/lib/primitives/coin.js
+++ b/lib/primitives/coin.js
@@ -49,7 +49,7 @@ function Coin(options) {
     this.fromOptions(options);
 }
 
-util.inherits(Coin, Output);
+Object.setPrototypeOf(Coin.prototype, Output.prototype);
 
 /**
  * Inject options into coin.
diff --git a/lib/primitives/headers.js b/lib/primitives/headers.js
index 2c5ce7fc..ecbda889 100644
--- a/lib/primitives/headers.js
+++ b/lib/primitives/headers.js
@@ -30,7 +30,7 @@ function Headers(options) {
     this.parseOptions(options);
 }
 
-util.inherits(Headers, AbstractBlock);
+Object.setPrototypeOf(Headers.prototype, AbstractBlock.prototype);
 
 /**
  * Do non-contextual verification on the headers.
diff --git a/lib/primitives/memblock.js b/lib/primitives/memblock.js
index c72f0e67..fb91ec68 100644
--- a/lib/primitives/memblock.js
+++ b/lib/primitives/memblock.js
@@ -7,11 +7,10 @@
 
 'use strict';
 
-const util = require('../utils/util');
 const AbstractBlock = require('./abstractblock');
 const Block = require('./block');
-const Script = require('../script/script');
 const Headers = require('./headers');
+const Script = require('../script/script');
 const BufferReader = require('../utils/reader');
 const DUMMY = Buffer.alloc(0);
 
@@ -45,7 +44,7 @@ function MemBlock() {
   this._raw = DUMMY;
 }
 
-util.inherits(MemBlock, AbstractBlock);
+Object.setPrototypeOf(MemBlock.prototype, AbstractBlock.prototype);
 
 /**
  * Test whether the block is a memblock.
diff --git a/lib/primitives/merkleblock.js b/lib/primitives/merkleblock.js
index 8800e115..0d7b094e 100644
--- a/lib/primitives/merkleblock.js
+++ b/lib/primitives/merkleblock.js
@@ -43,7 +43,7 @@ function MerkleBlock(options) {
     this.fromOptions(options);
 }
 
-util.inherits(MerkleBlock, AbstractBlock);
+Object.setPrototypeOf(MerkleBlock.prototype, AbstractBlock.prototype);
 
 /**
  * Inject properties from options object.
diff --git a/lib/primitives/mtx.js b/lib/primitives/mtx.js
index f41c66cd..f81fd308 100644
--- a/lib/primitives/mtx.js
+++ b/lib/primitives/mtx.js
@@ -56,7 +56,7 @@ function MTX(options) {
     this.fromOptions(options);
 }
 
-util.inherits(MTX, TX);
+Object.setPrototypeOf(MTX.prototype, TX.prototype);
 
 /**
  * Inject properties from options object.
@@ -1818,7 +1818,7 @@ function FundingError(msg, available, required) {
     Error.captureStackTrace(this, FundingError);
 }
 
-util.inherits(FundingError, Error);
+Object.setPrototypeOf(FundingError.prototype, Error.prototype);
 
 /*
  * Helpers
diff --git a/lib/protocol/errors.js b/lib/protocol/errors.js
index bafdc6ec..765e4356 100644
--- a/lib/protocol/errors.js
+++ b/lib/protocol/errors.js
@@ -12,7 +12,6 @@
  */
 
 const assert = require('assert');
-const util = require('../utils/util');
 
 /**
  * An error thrown during verification. Can be either
@@ -57,7 +56,7 @@ function VerifyError(msg, code, reason, score, malleated) {
     Error.captureStackTrace(this, VerifyError);
 }
 
-util.inherits(VerifyError, Error);
+Object.setPrototypeOf(VerifyError.prototype, Error.prototype);
 
 /*
  * Expose
diff --git a/lib/protocol/timedata.js b/lib/protocol/timedata.js
index 8d8a30e7..ddefcc14 100644
--- a/lib/protocol/timedata.js
+++ b/lib/protocol/timedata.js
@@ -40,7 +40,7 @@ function TimeData(limit) {
   this.checked = false;
 }
 
-util.inherits(TimeData, EventEmitter);
+Object.setPrototypeOf(TimeData.prototype, EventEmitter.prototype);
 
 /**
  * Add time data.
diff --git a/lib/script/common.js b/lib/script/common.js
index 72fbb45a..0fb0186c 100644
--- a/lib/script/common.js
+++ b/lib/script/common.js
@@ -834,4 +834,4 @@ exports.ScriptError = function ScriptError(code, op, ip) {
     Error.captureStackTrace(this, ScriptError);
 };
 
-util.inherits(exports.ScriptError, Error);
+Object.setPrototypeOf(exports.ScriptError.prototype, Error.prototype);
diff --git a/lib/utils/asyncobject.js b/lib/utils/asyncobject.js
index 1ee2286a..3e306f42 100644
--- a/lib/utils/asyncobject.js
+++ b/lib/utils/asyncobject.js
@@ -8,7 +8,6 @@
 
 const assert = require('assert');
 const EventEmitter = require('events');
-const util = require('./util');
 const Lock = require('./lock');
 
 /**
@@ -34,7 +33,7 @@ function AsyncObject() {
   this.loaded = false;
 }
 
-util.inherits(AsyncObject, EventEmitter);
+Object.setPrototypeOf(AsyncObject.prototype, EventEmitter.prototype);
 
 /**
  * Open the object (recallable).
diff --git a/lib/utils/encoding.js b/lib/utils/encoding.js
index c46e8aac..c5e56e06 100644
--- a/lib/utils/encoding.js
+++ b/lib/utils/encoding.js
@@ -12,7 +12,6 @@
  */
 
 const BN = require('bn.js');
-const util = require('./util');
 const MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER;
 const encoding = exports;
 
@@ -1038,7 +1037,7 @@ encoding.EncodingError = function EncodingError(offset, reason) {
     Error.captureStackTrace(this, EncodingError);
 };
 
-util.inherits(encoding.EncodingError, Error);
+Object.setPrototypeOf(encoding.EncodingError.prototype, Error.prototype);
 
 /*
  * Helpers
diff --git a/lib/utils/protoreader.js b/lib/utils/protoreader.js
index 8a34f128..28bb9c57 100644
--- a/lib/utils/protoreader.js
+++ b/lib/utils/protoreader.js
@@ -7,7 +7,6 @@
 'use strict';
 
 const assert = require('assert');
-const util = require('../utils/util');
 const BufferReader = require('../utils/reader');
 
 /*
@@ -36,7 +35,7 @@ function ProtoReader(data, zeroCopy) {
   BufferReader.call(this, data, zeroCopy);
 }
 
-util.inherits(ProtoReader, BufferReader);
+Object.setPrototypeOf(ProtoReader.prototype, BufferReader.prototype);
 
 ProtoReader.prototype.readVarint = function _readVarint() {
   const {size, value} = readVarint(this.data, this.offset);
diff --git a/lib/utils/protowriter.js b/lib/utils/protowriter.js
index aaa8ad60..5950d227 100644
--- a/lib/utils/protowriter.js
+++ b/lib/utils/protowriter.js
@@ -11,7 +11,6 @@
  */
 
 const assert = require('assert');
-const util = require('../utils/util');
 const BufferWriter = require('../utils/writer');
 
 /*
@@ -40,7 +39,7 @@ function ProtoWriter() {
   BufferWriter.call(this);
 }
 
-util.inherits(ProtoWriter, BufferWriter);
+Object.setPrototypeOf(ProtoWriter.prototype, BufferWriter.prototype);
 
 ProtoWriter.prototype.writeVarint = function _writeVarint(num) {
   const size = sizeVarint(num);
diff --git a/lib/utils/util.js b/lib/utils/util.js
index 3d57d481..bb955f88 100644
--- a/lib/utils/util.js
+++ b/lib/utils/util.js
@@ -509,21 +509,6 @@ util.mb = function mb(size) {
   return Math.floor(size / 1024 / 1024);
 };
 
-/**
- * Inheritance.
- * @param {Function} child - Constructor to inherit.
- * @param {Function} parent - Parent constructor.
- */
-
-util.inherits = function inherits(child, parent) {
-  child.super_ = parent;
-  Object.setPrototypeOf(child.prototype, parent.prototype);
-  Object.defineProperty(child.prototype, 'constructor', {
-    value: child,
-    enumerable: false
-  });
-};
-
 /**
  * Find index of a buffer in an array of buffers.
  * @param {Buffer[]} items
diff --git a/lib/utils/validator.js b/lib/utils/validator.js
index 3ec7d5f9..3603eb20 100644
--- a/lib/utils/validator.js
+++ b/lib/utils/validator.js
@@ -689,7 +689,7 @@ function ValidationError(key, type) {
     Error.captureStackTrace(this, ValidationError);
 }
 
-util.inherits(ValidationError, Error);
+Object.setPrototypeOf(ValidationError.prototype, Error.prototype);
 
 /*
  * Expose
diff --git a/lib/wallet/client.js b/lib/wallet/client.js
index 04c74c54..e5281f92 100644
--- a/lib/wallet/client.js
+++ b/lib/wallet/client.js
@@ -44,7 +44,7 @@ function WalletClient(options) {
   this.socket = null;
 }
 
-util.inherits(WalletClient, AsyncObject);
+Object.setPrototypeOf(WalletClient.prototype, AsyncObject.prototype);
 
 /**
  * Open the client, wait for socket to connect.
diff --git a/lib/wallet/http.js b/lib/wallet/http.js
index 0c650b85..6f60391e 100644
--- a/lib/wallet/http.js
+++ b/lib/wallet/http.js
@@ -52,7 +52,7 @@ function HTTPServer(options) {
   this.init();
 }
 
-util.inherits(HTTPServer, HTTPBase);
+Object.setPrototypeOf(HTTPServer.prototype, HTTPBase.prototype);
 
 /**
  * Attach to server.
diff --git a/lib/wallet/nodeclient.js b/lib/wallet/nodeclient.js
index 17e3a721..d28cca2e 100644
--- a/lib/wallet/nodeclient.js
+++ b/lib/wallet/nodeclient.js
@@ -6,7 +6,6 @@
 
 'use strict';
 
-const util = require('../utils/util');
 const AsyncObject = require('../utils/asyncobject');
 
 /**
@@ -30,7 +29,7 @@ function NodeClient(node) {
   this._init();
 }
 
-util.inherits(NodeClient, AsyncObject);
+Object.setPrototypeOf(NodeClient.prototype, AsyncObject.prototype);
 
 /**
  * Initialize the client.
diff --git a/lib/wallet/rpc.js b/lib/wallet/rpc.js
index 8c5218ad..4d13174e 100644
--- a/lib/wallet/rpc.js
+++ b/lib/wallet/rpc.js
@@ -54,7 +54,7 @@ function RPC(wdb) {
   this.init();
 }
 
-util.inherits(RPC, RPCBase);
+Object.setPrototypeOf(RPC.prototype, RPCBase.prototype);
 
 RPC.prototype.init = function init() {
   this.add('help', this.help);
diff --git a/lib/wallet/wallet.js b/lib/wallet/wallet.js
index be7faefc..5a506311 100644
--- a/lib/wallet/wallet.js
+++ b/lib/wallet/wallet.js
@@ -95,7 +95,7 @@ function Wallet(db, options) {
     this.fromOptions(options);
 }
 
-util.inherits(Wallet, EventEmitter);
+Object.setPrototypeOf(Wallet.prototype, EventEmitter.prototype);
 
 /**
  * Inject properties from options object.
diff --git a/lib/wallet/walletdb.js b/lib/wallet/walletdb.js
index a89fd5be..0dd42a7e 100644
--- a/lib/wallet/walletdb.js
+++ b/lib/wallet/walletdb.js
@@ -101,7 +101,7 @@ function WalletDB(options) {
   this._init();
 }
 
-util.inherits(WalletDB, AsyncObject);
+Object.setPrototypeOf(WalletDB.prototype, AsyncObject.prototype);
 
 /**
  * Database layout.
diff --git a/lib/wallet/walletkey.js b/lib/wallet/walletkey.js
index 008561be..92152339 100644
--- a/lib/wallet/walletkey.js
+++ b/lib/wallet/walletkey.js
@@ -7,7 +7,6 @@
 
 'use strict';
 
-const util = require('../utils/util');
 const Address = require('../primitives/address');
 const KeyRing = require('../primitives/keyring');
 const Path = require('./path');
@@ -35,7 +34,7 @@ function WalletKey(options, network) {
   this.index = -1;
 }
 
-util.inherits(WalletKey, KeyRing);
+Object.setPrototypeOf(WalletKey.prototype, KeyRing.prototype);
 
 /**
  * Instantiate key ring from options.
diff --git a/lib/workers/child-browser.js b/lib/workers/child-browser.js
index aac029c1..8e10f85d 100644
--- a/lib/workers/child-browser.js
+++ b/lib/workers/child-browser.js
@@ -8,7 +8,6 @@
 
 const assert = require('assert');
 const EventEmitter = require('events');
-const util = require('../utils/util');
 
 /**
  * Represents a child process.
@@ -27,7 +26,7 @@ function Child(file) {
   this.init(file);
 }
 
-util.inherits(Child, EventEmitter);
+Object.setPrototypeOf(Child.prototype, EventEmitter.prototype);
 
 /**
  * Test whether child process support is available.
diff --git a/lib/workers/child.js b/lib/workers/child.js
index 6b1430aa..02aad7f1 100644
--- a/lib/workers/child.js
+++ b/lib/workers/child.js
@@ -9,7 +9,6 @@
 const EventEmitter = require('events');
 const path = require('path');
 const cp = require('child_process');
-const util = require('../utils/util');
 
 const children = new Set();
 let exitBound = false;
@@ -33,7 +32,7 @@ function Child(file) {
   this.init(file);
 }
 
-util.inherits(Child, EventEmitter);
+Object.setPrototypeOf(Child.prototype, EventEmitter.prototype);
 
 /**
  * Test whether child process support is available.
diff --git a/lib/workers/master.js b/lib/workers/master.js
index 7303d860..9cc109f6 100644
--- a/lib/workers/master.js
+++ b/lib/workers/master.js
@@ -38,7 +38,7 @@ function Master() {
   this.init();
 }
 
-util.inherits(Master, EventEmitter);
+Object.setPrototypeOf(Master.prototype, EventEmitter.prototype);
 
 /**
  * Initialize master. Bind events.
diff --git a/lib/workers/packets.js b/lib/workers/packets.js
index 0cba880d..ba0503b5 100644
--- a/lib/workers/packets.js
+++ b/lib/workers/packets.js
@@ -11,7 +11,6 @@
  */
 
 const assert = require('assert');
-const util = require('../utils/util');
 const BufferReader = require('../utils/reader');
 const encoding = require('../utils/encoding');
 const Script = require('../script/script');
@@ -79,7 +78,7 @@ function EnvPacket(env) {
   this.json = JSON.stringify(this.env);
 }
 
-util.inherits(EnvPacket, Packet);
+Object.setPrototypeOf(EnvPacket.prototype, Packet.prototype);
 
 EnvPacket.prototype.cmd = packetTypes.ENV;
 
@@ -110,7 +109,7 @@ function EventPacket(items) {
   this.json = JSON.stringify(this.items);
 }
 
-util.inherits(EventPacket, Packet);
+Object.setPrototypeOf(EventPacket.prototype, Packet.prototype);
 
 EventPacket.prototype.cmd = packetTypes.EVENT;
 
@@ -140,7 +139,7 @@ function LogPacket(text) {
   this.text = text || '';
 }
 
-util.inherits(LogPacket, Packet);
+Object.setPrototypeOf(LogPacket.prototype, Packet.prototype);
 
 LogPacket.prototype.cmd = packetTypes.LOG;
 
@@ -169,7 +168,7 @@ function ErrorPacket(error) {
   this.error = error || new Error();
 }
 
-util.inherits(ErrorPacket, Packet);
+Object.setPrototypeOf(ErrorPacket.prototype, Packet.prototype);
 
 ErrorPacket.prototype.cmd = packetTypes.ERROR;
 
@@ -249,7 +248,7 @@ function ErrorResultPacket(error) {
   ErrorPacket.call(this, error);
 }
 
-util.inherits(ErrorResultPacket, ErrorPacket);
+Object.setPrototypeOf(ErrorResultPacket.prototype, ErrorPacket.prototype);
 
 ErrorResultPacket.prototype.cmd = packetTypes.ERRORRESULT;
 
@@ -265,7 +264,7 @@ function CheckPacket(tx, view, flags) {
   this.flags = flags != null ? flags : null;
 }
 
-util.inherits(CheckPacket, Packet);
+Object.setPrototypeOf(CheckPacket.prototype, Packet.prototype);
 
 CheckPacket.prototype.cmd = packetTypes.CHECK;
 
@@ -303,7 +302,7 @@ function CheckResultPacket(error) {
   this.error = error || null;
 }
 
-util.inherits(CheckResultPacket, Packet);
+Object.setPrototypeOf(CheckResultPacket.prototype, Packet.prototype);
 
 CheckResultPacket.prototype.cmd = packetTypes.CHECKRESULT;
 
@@ -379,7 +378,7 @@ function SignPacket(tx, rings, type) {
   this.type = type != null ? type : 1;
 }
 
-util.inherits(SignPacket, Packet);
+Object.setPrototypeOf(SignPacket.prototype, Packet.prototype);
 
 SignPacket.prototype.cmd = packetTypes.SIGN;
 
@@ -441,7 +440,7 @@ function SignResultPacket(total, witness, script) {
   this.witness = witness || [];
 }
 
-util.inherits(SignResultPacket, Packet);
+Object.setPrototypeOf(SignResultPacket.prototype, Packet.prototype);
 
 SignResultPacket.prototype.cmd = packetTypes.SIGNRESULT;
 
@@ -524,7 +523,7 @@ function CheckInputPacket(tx, index, coin, flags) {
   this.flags = flags != null ? flags : null;
 }
 
-util.inherits(CheckInputPacket, Packet);
+Object.setPrototypeOf(CheckInputPacket.prototype, Packet.prototype);
 
 CheckInputPacket.prototype.cmd = packetTypes.CHECKINPUT;
 
@@ -574,7 +573,9 @@ function CheckInputResultPacket(error) {
   CheckResultPacket.call(this, error);
 }
 
-util.inherits(CheckInputResultPacket, CheckResultPacket);
+Object.setPrototypeOf(
+  CheckInputResultPacket.prototype,
+  CheckResultPacket.prototype);
 
 CheckInputResultPacket.prototype.cmd = packetTypes.CHECKINPUTRESULT;
 
@@ -599,7 +600,7 @@ function SignInputPacket(tx, index, coin, ring, type) {
   this.type = type != null ? type : 1;
 }
 
-util.inherits(SignInputPacket, Packet);
+Object.setPrototypeOf(SignInputPacket.prototype, Packet.prototype);
 
 SignInputPacket.prototype.cmd = packetTypes.SIGNINPUT;
 
@@ -652,7 +653,7 @@ function SignInputResultPacket(value, witness, script) {
   this.witness = witness || null;
 }
 
-util.inherits(SignInputResultPacket, Packet);
+Object.setPrototypeOf(SignInputResultPacket.prototype, Packet.prototype);
 
 SignInputResultPacket.prototype.cmd = packetTypes.SIGNINPUTRESULT;
 
@@ -706,7 +707,7 @@ function ECVerifyPacket(msg, sig, key) {
   this.key = key || null;
 }
 
-util.inherits(ECVerifyPacket, Packet);
+Object.setPrototypeOf(ECVerifyPacket.prototype, Packet.prototype);
 
 ECVerifyPacket.prototype.cmd = packetTypes.ECVERIFY;
 
@@ -743,7 +744,7 @@ function ECVerifyResultPacket(value) {
   this.value = value;
 }
 
-util.inherits(ECVerifyResultPacket, Packet);
+Object.setPrototypeOf(ECVerifyResultPacket.prototype, Packet.prototype);
 
 ECVerifyResultPacket.prototype.cmd = packetTypes.ECVERIFYRESULT;
 
@@ -773,7 +774,7 @@ function ECSignPacket(msg, key) {
   this.key = key || null;
 }
 
-util.inherits(ECSignPacket, Packet);
+Object.setPrototypeOf(ECSignPacket.prototype, Packet.prototype);
 
 ECSignPacket.prototype.cmd = packetTypes.ECSIGN;
 
@@ -807,7 +808,7 @@ function ECSignResultPacket(sig) {
   this.sig = sig;
 }
 
-util.inherits(ECSignResultPacket, Packet);
+Object.setPrototypeOf(ECSignResultPacket.prototype, Packet.prototype);
 
 ECSignResultPacket.prototype.cmd = packetTypes.ECSIGNRESULT;
 
@@ -839,7 +840,7 @@ function MinePacket(data, target, min, max) {
   this.max = max != null ? max : -1;
 }
 
-util.inherits(MinePacket, Packet);
+Object.setPrototypeOf(MinePacket.prototype, Packet.prototype);
 
 MinePacket.prototype.cmd = packetTypes.MINE;
 
@@ -874,7 +875,7 @@ function MineResultPacket(nonce) {
   this.nonce = nonce != null ? nonce : -1;
 }
 
-util.inherits(MineResultPacket, Packet);
+Object.setPrototypeOf(MineResultPacket.prototype, Packet.prototype);
 
 MineResultPacket.prototype.cmd = packetTypes.MINERESULT;
 
@@ -910,7 +911,7 @@ function ScryptPacket(passwd, salt, N, r, p, len) {
   this.len = len != null ? len : -1;
 }
 
-util.inherits(ScryptPacket, Packet);
+Object.setPrototypeOf(ScryptPacket.prototype, Packet.prototype);
 
 ScryptPacket.prototype.cmd = packetTypes.SCRYPT;
 
@@ -953,7 +954,7 @@ function ScryptResultPacket(key) {
   this.key = key || null;
 }
 
-util.inherits(ScryptResultPacket, Packet);
+Object.setPrototypeOf(ScryptResultPacket.prototype, Packet.prototype);
 
 ScryptResultPacket.prototype.cmd = packetTypes.SCRYPTRESULT;
 
diff --git a/lib/workers/parent-browser.js b/lib/workers/parent-browser.js
index 5c811135..2eb865e7 100644
--- a/lib/workers/parent-browser.js
+++ b/lib/workers/parent-browser.js
@@ -8,7 +8,6 @@
 
 const assert = require('assert');
 const EventEmitter = require('events');
-const util = require('../utils/util');
 
 /**
  * Represents the parent process.
@@ -26,7 +25,7 @@ function Parent() {
   this.init();
 }
 
-util.inherits(Parent, EventEmitter);
+Object.setPrototypeOf(Parent.prototype, EventEmitter.prototype);
 
 /**
  * Initialize master (web workers).
diff --git a/lib/workers/parent.js b/lib/workers/parent.js
index 77dc6ed8..c0868680 100644
--- a/lib/workers/parent.js
+++ b/lib/workers/parent.js
@@ -7,7 +7,6 @@
 'use strict';
 
 const EventEmitter = require('events');
-const util = require('../utils/util');
 
 /**
  * Represents the parent process.
@@ -24,7 +23,7 @@ function Parent() {
   this.init();
 }
 
-util.inherits(Parent, EventEmitter);
+Object.setPrototypeOf(Parent.prototype, EventEmitter.prototype);
 
 /**
  * Initialize master (node.js).
diff --git a/lib/workers/parser.js b/lib/workers/parser.js
index f9c9672f..b70a2908 100644
--- a/lib/workers/parser.js
+++ b/lib/workers/parser.js
@@ -9,7 +9,6 @@
 
 const assert = require('assert');
 const EventEmitter = require('events');
-const util = require('../utils/util');
 const packets = require('./packets');
 
 /**
@@ -30,7 +29,7 @@ function Parser() {
   this.total = 0;
 }
 
-util.inherits(Parser, EventEmitter);
+Object.setPrototypeOf(Parser.prototype, EventEmitter.prototype);
 
 Parser.prototype.feed = function feed(data) {
   this.total += data.length;
diff --git a/lib/workers/workerpool.js b/lib/workers/workerpool.js
index 8d62e1b0..05ce36d8 100644
--- a/lib/workers/workerpool.js
+++ b/lib/workers/workerpool.js
@@ -51,7 +51,7 @@ function WorkerPool(options) {
   this.set(options);
 }
 
-util.inherits(WorkerPool, EventEmitter);
+Object.setPrototypeOf(WorkerPool.prototype, EventEmitter.prototype);
 
 /**
  * Set worker pool options.
@@ -378,7 +378,7 @@ function Worker(file) {
   this.init();
 }
 
-util.inherits(Worker, EventEmitter);
+Object.setPrototypeOf(Worker.prototype, EventEmitter.prototype);
 
 /**
  * Initialize worker. Bind to events.