diff --git a/client.js b/client.js
index 8db3488..9baadb8 100644
--- a/client.js
+++ b/client.js
@@ -1,12 +1,12 @@
-var levelup = require('levelup')
-var encode = require('encoding-down')
-var leveldown = require('./leveldown')
+const levelup = require('levelup')
+const encode = require('encoding-down')
+const leveldown = require('./leveldown')
 
 module.exports = function (opts) {
   if (!opts) opts = {}
 
-  var down = leveldown(Object.assign({}, opts, { onflush: onflush }))
-  var db = levelup(encode(down, opts), opts)
+  const down = leveldown(Object.assign({}, opts, { onflush: onflush }))
+  const db = levelup(encode(down, opts), opts)
 
   db.createRpcStream = db.connect = connect
   db.isFlushed = isFlushed
diff --git a/leveldown.js b/leveldown.js
index e65ce71..7903a29 100644
--- a/leveldown.js
+++ b/leveldown.js
@@ -1,14 +1,14 @@
-var duplexify = require('duplexify')
-var abstract = require('abstract-leveldown')
-var util = require('util')
-var eos = require('end-of-stream')
-var ids = require('numeric-id-map')
-var lpstream = require('length-prefixed-stream')
-var reachdown = require('reachdown')
-var messages = require('./messages')
-var matchdown = require('./matchdown')
-
-var ENCODERS = [
+const duplexify = require('duplexify')
+const abstract = require('abstract-leveldown')
+const util = require('util')
+const eos = require('end-of-stream')
+const ids = require('numeric-id-map')
+const lpstream = require('length-prefixed-stream')
+const reachdown = require('reachdown')
+const messages = require('./messages')
+const matchdown = require('./matchdown')
+
+const ENCODERS = [
   messages.Get,
   messages.Put,
   messages.Delete,
@@ -16,7 +16,7 @@ var ENCODERS = [
   messages.Iterator
 ]
 
-var DECODERS = [
+const DECODERS = [
   messages.Callback,
   messages.IteratorData
 ]
@@ -47,18 +47,19 @@ Multilevel.prototype.createRpcStream = function (opts, proxy) {
   if (!opts) opts = {}
   this._ref = opts.ref || null
 
-  var self = this
-  var encode = this._encode
-  var decode = lpstream.decode()
+  const self = this
+  const encode = this._encode
+  const decode = lpstream.decode()
 
   decode.on('data', function (data) {
     if (!data.length) return
-    var tag = data[0]
+    const tag = data[0]
     if (tag >= DECODERS.length) return
 
-    var dec = DECODERS[tag]
+    const dec = DECODERS[tag]
+    let res
     try {
-      var res = dec.decode(data, 1)
+      res = dec.decode(data, 1)
     } catch (err) {
       return
     }
@@ -93,14 +94,14 @@ Multilevel.prototype.createRpcStream = function (opts, proxy) {
       return
     }
 
-    for (var i = 0; i < self._requests.length; i++) {
-      var req = self._requests.get(i)
+    for (let i = 0; i < self._requests.length; i++) {
+      const req = self._requests.get(i)
       if (!req) continue
       self._write(req)
     }
 
-    for (var j = 0; j < self._iterators.length; j++) {
-      var ite = self._iterators.get(j)
+    for (let j = 0; j < self._iterators.length; j++) {
+      const ite = self._iterators.get(j)
       if (!ite) continue
       ite.options = ite.iterator._options
       self._write(ite)
@@ -108,14 +109,14 @@ Multilevel.prototype.createRpcStream = function (opts, proxy) {
   }
 
   function oniteratordata (res) {
-    var req = self._iterators.get(res.id)
+    const req = self._iterators.get(res.id)
     if (!req) return
     req.pending.push(res)
     if (req.callback) req.iterator.next(req.callback)
   }
 
   function oncallback (res) {
-    var req = self._requests.remove(res.id)
+    const req = self._requests.remove(res.id)
     if (req) req.callback(decodeError(res.error), decodeValue(res.value, req.valueAsBuffer))
   }
 }
@@ -135,13 +136,13 @@ Multilevel.prototype._flushMaybe = function () {
 }
 
 Multilevel.prototype._clearRequests = function (closing) {
-  for (var i = 0; i < this._requests.length; i++) {
-    var req = this._requests.remove(i)
+  for (let i = 0; i < this._requests.length; i++) {
+    const req = this._requests.remove(i)
     if (req) req.callback(new Error('Connection to leader lost'))
   }
 
-  for (var j = 0; j < this._iterators.length; j++) {
-    var ite = this._iterators.remove(j)
+  for (let j = 0; j < this._iterators.length; j++) {
+    const ite = this._iterators.remove(j)
     if (ite) {
       if (ite.callback && !closing) ite.callback(new Error('Connection to leader lost'))
       ite.iterator.end()
@@ -160,7 +161,7 @@ Multilevel.prototype._serializeValue = function (value) {
 Multilevel.prototype._get = function (key, opts, cb) {
   if (this._db) return this._db._get(key, opts, cb)
 
-  var req = {
+  const req = {
     tag: 0,
     id: 0,
     key: key,
@@ -175,7 +176,7 @@ Multilevel.prototype._get = function (key, opts, cb) {
 Multilevel.prototype._put = function (key, value, opts, cb) {
   if (this._db) return this._db._put(key, value, opts, cb)
 
-  var req = {
+  const req = {
     tag: 1,
     id: 0,
     key: key,
@@ -190,7 +191,7 @@ Multilevel.prototype._put = function (key, value, opts, cb) {
 Multilevel.prototype._del = function (key, opts, cb) {
   if (this._db) return this._db._del(key, opts, cb)
 
-  var req = {
+  const req = {
     tag: 2,
     id: 0,
     key: key,
@@ -204,7 +205,7 @@ Multilevel.prototype._del = function (key, opts, cb) {
 Multilevel.prototype._batch = function (batch, opts, cb) {
   if (this._db) return this._db._batch(batch, opts, cb)
 
-  var req = {
+  const req = {
     tag: 3,
     id: 0,
     ops: batch,
@@ -217,8 +218,8 @@ Multilevel.prototype._batch = function (batch, opts, cb) {
 
 Multilevel.prototype._write = function (req) {
   if (this._requests.length + this._iterators.length === 1) ref(this._ref)
-  var enc = ENCODERS[req.tag]
-  var buf = Buffer.allocUnsafe(enc.encodingLength(req) + 1)
+  const enc = ENCODERS[req.tag]
+  const buf = Buffer.allocUnsafe(enc.encodingLength(req) + 1)
   buf[0] = req.tag
   enc.encode(req, buf, 1)
   this._encode.write(buf)
@@ -250,7 +251,7 @@ function Iterator (parent, opts) {
   this._valueAsBuffer = opts.valueAsBuffer
   this._options = opts
 
-  var req = {
+  const req = {
     tag: 4,
     id: 0,
     batch: 32,
@@ -279,7 +280,7 @@ Iterator.prototype.next = function (cb) {
       this._parent._write(this._req)
     }
 
-    var next = this._req.pending.shift()
+    const next = this._req.pending.shift()
     if (next.error) return cb(decodeError(next.error))
 
     if (!next.key && !next.value) return cb()
@@ -287,8 +288,8 @@ Iterator.prototype.next = function (cb) {
     this._options.gt = next.key
     if (this._options.limit > 0) this._options.limit--
 
-    var key = decodeValue(next.key, this._keyAsBuffer)
-    var val = decodeValue(next.value, this._valueAsBuffer)
+    const key = decodeValue(next.key, this._keyAsBuffer)
+    const val = decodeValue(next.value, this._valueAsBuffer)
     return cb(undefined, key, val)
   }
 
diff --git a/package.json b/package.json
index 735c313..acc105f 100644
--- a/package.json
+++ b/package.json
@@ -34,9 +34,9 @@
     "level-community": "^3.0.0",
     "level-compose": "^0.0.2",
     "memdown": "^5.0.0",
-    "nyc": "^14.1.1",
+    "nyc": "^15.1.0",
     "protocol-buffers": "^4.0.2",
-    "standard": "^14.1.0",
+    "standard": "^16.0.3",
     "subleveldown": "^5.0.1",
     "tape": "^5.0.1"
   },
@@ -52,6 +52,11 @@
   },
   "homepage": "https://github.com/Level/multileveldown",
   "engines": {
-    "node": ">=8"
+    "node": ">=10"
+  },
+  "standard": {
+    "ignore": [
+      "messages.js"
+    ]
   }
 }
diff --git a/server.js b/server.js
index ec74bc5..3fe0825 100644
--- a/server.js
+++ b/server.js
@@ -1,12 +1,12 @@
-var lpstream = require('length-prefixed-stream')
-var eos = require('end-of-stream')
-var duplexify = require('duplexify')
-var reachdown = require('reachdown')
-var messages = require('./messages')
-var rangeOptions = 'gt gte lt lte'.split(' ')
-var matchdown = require('./matchdown')
-
-var DECODERS = [
+const lpstream = require('length-prefixed-stream')
+const eos = require('end-of-stream')
+const duplexify = require('duplexify')
+const reachdown = require('reachdown')
+const messages = require('./messages')
+const rangeOptions = 'gt gte lt lte'.split(' ')
+const matchdown = require('./matchdown')
+
+const DECODERS = [
   messages.Get,
   messages.Put,
   messages.Delete,
@@ -17,14 +17,14 @@ var DECODERS = [
 module.exports = function (db, opts) {
   if (!opts) opts = {}
 
-  var readonly = !!(opts.readonly)
-  var decode = lpstream.decode()
-  var encode = lpstream.encode()
-  var stream = duplexify(decode, encode)
+  const readonly = !!(opts.readonly)
+  const decode = lpstream.decode()
+  const encode = lpstream.encode()
+  const stream = duplexify(decode, encode)
 
-  var preput = opts.preput || function (key, val, cb) { cb(null) }
-  var predel = opts.predel || function (key, cb) { cb(null) }
-  var prebatch = opts.prebatch || function (ops, cb) { cb(null) }
+  const preput = opts.preput || function (key, val, cb) { cb(null) }
+  const predel = opts.predel || function (key, cb) { cb(null) }
+  const prebatch = opts.prebatch || function (ops, cb) { cb(null) }
 
   if (db.isOpen()) ready()
   else db.open(ready)
@@ -32,24 +32,25 @@ module.exports = function (db, opts) {
   return stream
 
   function ready () {
-    var down = reachdown(db, matchdown, false)
-    var iterators = []
+    const down = reachdown(db, matchdown, false)
+    const iterators = []
 
     eos(stream, function () {
       while (iterators.length) {
-        var next = iterators.shift()
+        const next = iterators.shift()
         if (next) next.end()
       }
     })
 
     decode.on('data', function (data) {
       if (!data.length) return
-      var tag = data[0]
+      const tag = data[0]
       if (tag >= DECODERS.length) return
 
-      var dec = DECODERS[tag]
+      const dec = DECODERS[tag]
+      let req
       try {
-        var req = dec.decode(data, 1)
+        req = dec.decode(data, 1)
       } catch (err) {
         return
       }
@@ -74,8 +75,8 @@ module.exports = function (db, opts) {
     })
 
     function callback (id, err, value) {
-      var msg = { id: id, error: err && err.message, value: value }
-      var buf = Buffer.allocUnsafe(messages.Callback.encodingLength(msg) + 1)
+      const msg = { id: id, error: err && err.message, value: value }
+      const buf = Buffer.allocUnsafe(messages.Callback.encodingLength(msg) + 1)
       buf[0] = 0
       messages.Callback.encode(msg, buf, 1)
       encode.write(buf)
@@ -122,7 +123,7 @@ module.exports = function (db, opts) {
     function oniterator (req) {
       while (iterators.length < req.id) iterators.push(null)
 
-      var prev = iterators[req.id]
+      let prev = iterators[req.id]
       if (!prev) prev = iterators[req.id] = new Iterator(down, req, encode)
 
       if (!req.batch) {
@@ -137,7 +138,7 @@ module.exports = function (db, opts) {
 }
 
 function Iterator (down, req, encode) {
-  var self = this
+  const self = this
 
   this.batch = req.batch || 0
   this._iterator = down.iterator(cleanRangeOptions(req.options))
@@ -159,7 +160,7 @@ function Iterator (down, req, encode) {
     self._data.key = key
     self._data.value = value
     self.batch--
-    var buf = Buffer.allocUnsafe(messages.IteratorData.encodingLength(self._data) + 1)
+    const buf = Buffer.allocUnsafe(messages.IteratorData.encodingLength(self._data) + 1)
     buf[0] = 1
     messages.IteratorData.encode(self._data, buf, 1)
     encode.write(buf)
@@ -185,9 +186,9 @@ function noop () {}
 function cleanRangeOptions (options) {
   if (!options) return
 
-  var result = {}
+  const result = {}
 
-  for (var k in options) {
+  for (const k in options) {
     if (!hasOwnProperty.call(options, k)) continue
 
     if (!isRangeOption(k) || options[k] != null) {
diff --git a/streams.js b/streams.js
index 9b275ab..642b412 100644
--- a/streams.js
+++ b/streams.js
@@ -1,5 +1,5 @@
-var pbs = require('pbs')
-var fs = require('fs')
-var path = require('path')
+const pbs = require('pbs')
+const fs = require('fs')
+const path = require('path')
 
 module.exports = pbs(fs.readFileSync(path.join(__dirname, 'schema.proto')))
diff --git a/test/abstract.js b/test/abstract.js
index a6a5b96..b53cbc9 100644
--- a/test/abstract.js
+++ b/test/abstract.js
@@ -1,17 +1,17 @@
-var test = require('tape')
-var memdown = require('memdown')
-var levelup = require('levelup')
-var encode = require('encoding-down')
-var factory = require('level-compose')(memdown, encode, levelup)
-var multileveldown = require('..')
-var suite = require('abstract-leveldown/test')
+const test = require('tape')
+const memdown = require('memdown')
+const levelup = require('levelup')
+const encode = require('encoding-down')
+const factory = require('level-compose')(memdown, encode, levelup)
+const multileveldown = require('..')
+const suite = require('abstract-leveldown/test')
 
 suite({
   test: test,
   factory: function () {
-    var db = factory()
-    var stream = multileveldown.server(db)
-    var client = multileveldown.client()
+    const db = factory()
+    const stream = multileveldown.server(db)
+    const client = multileveldown.client()
 
     stream.pipe(client.createRpcStream()).pipe(stream)
 
diff --git a/test/basic.js b/test/basic.js
index 653447c..e7a9738 100644
--- a/test/basic.js
+++ b/test/basic.js
@@ -1,17 +1,17 @@
-var tape = require('tape')
-var memdown = require('memdown')
-var concat = require('concat-stream')
-var levelup = require('levelup')
-var encode = require('encoding-down')
-var factory = require('level-compose')(memdown, encode, levelup)
-var multileveldown = require('../')
+const tape = require('tape')
+const memdown = require('memdown')
+const concat = require('concat-stream')
+const levelup = require('levelup')
+const encode = require('encoding-down')
+const factory = require('level-compose')(memdown, encode, levelup)
+const multileveldown = require('../')
 
 tape('get', function (t) {
   t.plan(7)
 
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -36,9 +36,9 @@ tape('get', function (t) {
 })
 
 tape('get with valueEncoding: json in constructor', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client({ valueEncoding: 'json' })
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client({ valueEncoding: 'json' })
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -54,9 +54,9 @@ tape('get with valueEncoding: json in constructor', function (t) {
 tape('get with valueEncoding: json in get options', function (t) {
   t.plan(5)
 
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -76,9 +76,9 @@ tape('get with valueEncoding: json in get options', function (t) {
 })
 
 tape('put', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -95,9 +95,9 @@ tape('put', function (t) {
 tape('put with valueEncoding: json in constructor', function (t) {
   t.plan(5)
 
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client({ valueEncoding: 'json' })
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client({ valueEncoding: 'json' })
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -119,9 +119,9 @@ tape('put with valueEncoding: json in constructor', function (t) {
 tape('put with valueEncoding: json in put options', function (t) {
   t.plan(5)
 
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -141,12 +141,12 @@ tape('put with valueEncoding: json in put options', function (t) {
 })
 
 tape('readonly', function (t) {
-  var db = factory()
+  const db = factory()
 
   db.put('hello', 'verden')
 
-  var stream = multileveldown.server(db, { readonly: true })
-  var client = multileveldown.client()
+  const stream = multileveldown.server(db, { readonly: true })
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -161,9 +161,9 @@ tape('readonly', function (t) {
 })
 
 tape('del', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -181,9 +181,9 @@ tape('del', function (t) {
 })
 
 tape('batch', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -202,15 +202,15 @@ tape('batch', function (t) {
 })
 
 tape('read stream', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
   client.batch([{ type: 'put', key: 'hello', value: 'world' }, { type: 'put', key: 'hej', value: 'verden' }], function (err) {
     t.error(err, 'no err')
-    var rs = client.createReadStream()
+    const rs = client.createReadStream()
     rs.pipe(concat(function (datas) {
       t.same(datas.length, 2)
       t.same(datas[0], { key: 'hej', value: 'verden' })
@@ -221,15 +221,15 @@ tape('read stream', function (t) {
 })
 
 tape('read stream (gt)', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
   client.batch([{ type: 'put', key: 'hello', value: 'world' }, { type: 'put', key: 'hej', value: 'verden' }], function (err) {
     t.error(err, 'no err')
-    var rs = client.createReadStream({ gt: 'hej' })
+    const rs = client.createReadStream({ gt: 'hej' })
     rs.pipe(concat(function (datas) {
       t.same(datas.length, 1)
       t.same(datas[0], { key: 'hello', value: 'world' })
diff --git a/test/concurrent.js b/test/concurrent.js
index e3290c7..4724f98 100644
--- a/test/concurrent.js
+++ b/test/concurrent.js
@@ -1,26 +1,26 @@
-var tape = require('tape')
-var memdown = require('memdown')
-var levelup = require('levelup')
-var concat = require('concat-stream')
-var multileveldown = require('../')
-var encode = require('encoding-down')
-var factory = require('level-compose')(memdown, encode, levelup)
+const tape = require('tape')
+const memdown = require('memdown')
+const levelup = require('levelup')
+const concat = require('concat-stream')
+const multileveldown = require('../')
+const encode = require('encoding-down')
+const factory = require('level-compose')(memdown, encode, levelup)
 
 tape('two concurrent iterators', function (t) {
-  var db = factory()
-  var server = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const server = multileveldown.server(db)
+  const client = multileveldown.client()
 
   server.pipe(client.connect()).pipe(server)
 
-  var batch = []
-  for (var i = 0; i < 100; i++) batch.push({ type: 'put', key: 'key-' + i, value: 'value-' + i })
+  const batch = []
+  for (let i = 0; i < 100; i++) batch.push({ type: 'put', key: 'key-' + i, value: 'value-' + i })
 
   client.batch(batch, function (err) {
     t.error(err)
 
-    var rs1 = client.createReadStream()
-    var rs2 = client.createReadStream()
+    const rs1 = client.createReadStream()
+    const rs2 = client.createReadStream()
 
     rs1.pipe(concat(function (list1) {
       t.same(list1.length, 100)
diff --git a/test/encryptdown.js b/test/encryptdown.js
index 795f19f..73bd568 100644
--- a/test/encryptdown.js
+++ b/test/encryptdown.js
@@ -1,13 +1,13 @@
-var tape = require('tape')
-var memdown = require('memdown')
-var concat = require('concat-stream')
-var levelup = require('levelup')
-var encode = require('encoding-down')
-var encrypt = require('@adorsys/encrypt-down')
-var factory = require('level-compose')(memdown, encrypt, encode, levelup)
-var multileveldown = require('../')
+const tape = require('tape')
+const memdown = require('memdown')
+const concat = require('concat-stream')
+const levelup = require('levelup')
+const encode = require('encoding-down')
+const encrypt = require('@adorsys/encrypt-down')
+const factory = require('level-compose')(memdown, encrypt, encode, levelup)
+const multileveldown = require('../')
 
-var jwk = {
+const jwk = {
   kty: 'oct',
   alg: 'A256GCM',
   use: 'enc',
@@ -21,9 +21,9 @@ var jwk = {
 tape('multileveldown server on encrypt-down', function (t) {
   t.plan(3)
 
-  var db = factory({ jwk })
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory({ jwk })
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -46,9 +46,9 @@ tape('multileveldown server on encrypt-down', function (t) {
 tape('multileveldown server on encrypt-down with encoding', function (t) {
   t.plan(3)
 
-  var db = factory({ jwk, valueEncoding: 'json' })
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client({ valueEncoding: 'json' })
+  const db = factory({ jwk, valueEncoding: 'json' })
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client({ valueEncoding: 'json' })
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
diff --git a/test/retry.js b/test/retry.js
index 8dee6df..9ea4b85 100644
--- a/test/retry.js
+++ b/test/retry.js
@@ -1,14 +1,14 @@
-var tape = require('tape')
-var memdown = require('memdown')
-var levelup = require('levelup')
-var multileveldown = require('../')
-var encode = require('encoding-down')
-var factory = require('level-compose')(memdown, encode, levelup)
+const tape = require('tape')
+const memdown = require('memdown')
+const levelup = require('levelup')
+const multileveldown = require('../')
+const encode = require('encoding-down')
+const factory = require('level-compose')(memdown, encode, levelup)
 
 tape('retry get', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client({ retry: true })
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client({ retry: true })
 
   db.put('hello', 'world', function () {
     client.get('hello', function (err, value) {
@@ -22,9 +22,9 @@ tape('retry get', function (t) {
 })
 
 tape('no retry get', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client({ retry: false })
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client({ retry: false })
 
   client.open(function () {
     db.put('hello', 'world', function () {
@@ -33,12 +33,12 @@ tape('no retry get', function (t) {
         t.end()
       })
 
-      var rpc = client.createRpcStream()
+      const rpc = client.createRpcStream()
       stream.pipe(rpc).pipe(stream)
       rpc.destroy()
 
       setTimeout(function () {
-        var rpc = client.createRpcStream()
+        const rpc = client.createRpcStream()
         stream.pipe(rpc).pipe(stream)
       }, 100)
     })
@@ -46,9 +46,9 @@ tape('no retry get', function (t) {
 })
 
 tape('retry get', function (t) {
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client({ retry: true })
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client({ retry: true })
 
   client.open(function () {
     db.put('hello', 'world', function () {
@@ -58,12 +58,12 @@ tape('retry get', function (t) {
         t.end()
       })
 
-      var rpc = client.createRpcStream()
+      const rpc = client.createRpcStream()
       stream.pipe(rpc).pipe(stream)
       rpc.destroy()
 
       setTimeout(function () {
-        var rpc = client.createRpcStream()
+        const rpc = client.createRpcStream()
         stream.pipe(rpc).pipe(stream)
       }, 100)
     })
@@ -71,8 +71,8 @@ tape('retry get', function (t) {
 })
 
 tape('retry read stream', function (t) {
-  var db = factory()
-  var client = multileveldown.client({ retry: true })
+  const db = factory()
+  const client = multileveldown.client({ retry: true })
 
   client.open(function () {
     db.batch([{
@@ -88,8 +88,8 @@ tape('retry read stream', function (t) {
       key: 'hola',
       value: 'mundo'
     }], function () {
-      var rs = client.createReadStream()
-      var expected = [{
+      const rs = client.createReadStream()
+      const expected = [{
         key: 'hej',
         value: 'verden'
       }, {
@@ -109,10 +109,10 @@ tape('retry read stream', function (t) {
         t.end()
       })
 
-      var stream
-      var clientStream
+      let stream
+      let clientStream
 
-      var connect = function () {
+      const connect = function () {
         stream = multileveldown.server(db)
         clientStream = client.createRpcStream()
 
@@ -126,8 +126,8 @@ tape('retry read stream', function (t) {
 })
 
 tape('retry read stream and limit', function (t) {
-  var db = factory()
-  var client = multileveldown.client({ retry: true })
+  const db = factory()
+  const client = multileveldown.client({ retry: true })
 
   client.open(function () {
     db.batch([{
@@ -143,8 +143,8 @@ tape('retry read stream and limit', function (t) {
       key: 'hola',
       value: 'mundo'
     }], function () {
-      var rs = client.createReadStream({ limit: 2 })
-      var expected = [{
+      const rs = client.createReadStream({ limit: 2 })
+      const expected = [{
         key: 'hej',
         value: 'verden'
       }, {
@@ -161,10 +161,10 @@ tape('retry read stream and limit', function (t) {
         t.end()
       })
 
-      var stream
-      var clientStream
+      let stream
+      let clientStream
 
-      var connect = function () {
+      const connect = function () {
         stream = multileveldown.server(db)
         clientStream = client.createRpcStream()
 
diff --git a/test/streams.js b/test/streams.js
index e3290c7..4724f98 100644
--- a/test/streams.js
+++ b/test/streams.js
@@ -1,26 +1,26 @@
-var tape = require('tape')
-var memdown = require('memdown')
-var levelup = require('levelup')
-var concat = require('concat-stream')
-var multileveldown = require('../')
-var encode = require('encoding-down')
-var factory = require('level-compose')(memdown, encode, levelup)
+const tape = require('tape')
+const memdown = require('memdown')
+const levelup = require('levelup')
+const concat = require('concat-stream')
+const multileveldown = require('../')
+const encode = require('encoding-down')
+const factory = require('level-compose')(memdown, encode, levelup)
 
 tape('two concurrent iterators', function (t) {
-  var db = factory()
-  var server = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const server = multileveldown.server(db)
+  const client = multileveldown.client()
 
   server.pipe(client.connect()).pipe(server)
 
-  var batch = []
-  for (var i = 0; i < 100; i++) batch.push({ type: 'put', key: 'key-' + i, value: 'value-' + i })
+  const batch = []
+  for (let i = 0; i < 100; i++) batch.push({ type: 'put', key: 'key-' + i, value: 'value-' + i })
 
   client.batch(batch, function (err) {
     t.error(err)
 
-    var rs1 = client.createReadStream()
-    var rs2 = client.createReadStream()
+    const rs1 = client.createReadStream()
+    const rs2 = client.createReadStream()
 
     rs1.pipe(concat(function (list1) {
       t.same(list1.length, 100)
diff --git a/test/subleveldown.js b/test/subleveldown.js
index e4cafe7..be1c381 100644
--- a/test/subleveldown.js
+++ b/test/subleveldown.js
@@ -1,20 +1,20 @@
-var tape = require('tape')
-var memdown = require('memdown')
-var concat = require('concat-stream')
-var levelup = require('levelup')
-var encode = require('encoding-down')
-var factory = require('level-compose')(memdown, encode, levelup)
-var sub = require('subleveldown')
-var multileveldown = require('../')
+const tape = require('tape')
+const memdown = require('memdown')
+const concat = require('concat-stream')
+const levelup = require('levelup')
+const encode = require('encoding-down')
+const factory = require('level-compose')(memdown, encode, levelup)
+const sub = require('subleveldown')
+const multileveldown = require('../')
 
 tape('subleveldown on deferred multileveldown client', function (t) {
   t.plan(5)
 
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
-  var sub1 = sub(client, 'test', { valueEncoding: 'json' })
-  var sub2 = sub(client, 'test')
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
+  const sub1 = sub(client, 'test', { valueEncoding: 'json' })
+  const sub2 = sub(client, 'test')
 
   t.is(client.isOpen(), false)
   stream.pipe(client.createRpcStream()).pipe(stream)
@@ -39,17 +39,17 @@ tape('subleveldown on deferred multileveldown client', function (t) {
 tape('subleveldown on non-deferred multileveldown client', function (t) {
   t.plan(5)
 
-  var db = factory()
-  var stream = multileveldown.server(db)
-  var client = multileveldown.client()
+  const db = factory()
+  const stream = multileveldown.server(db)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
   client.once('open', function () {
     t.is(client.isOpen(), true)
 
-    var sub1 = sub(client, 'test', { valueEncoding: 'json' })
-    var sub2 = sub(client, 'test')
+    const sub1 = sub(client, 'test', { valueEncoding: 'json' })
+    const sub2 = sub(client, 'test')
 
     sub1.put('hello', { test: 'world' }, function (err) {
       t.error(err, 'no err')
@@ -72,11 +72,11 @@ tape('subleveldown on non-deferred multileveldown client', function (t) {
 tape('multileveldown server on deferred subleveldown', function (t) {
   t.plan(4)
 
-  var db = factory()
-  var sub1 = sub(db, 'test1')
-  var sub2 = sub(db, 'test2')
-  var stream = multileveldown.server(sub1)
-  var client = multileveldown.client()
+  const db = factory()
+  const sub1 = sub(db, 'test1')
+  const sub2 = sub(db, 'test2')
+  const stream = multileveldown.server(sub1)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -103,13 +103,13 @@ tape('multileveldown server on deferred subleveldown', function (t) {
 tape('multileveldown server on non-deferred subleveldown', function (t) {
   t.plan(4)
 
-  var db = factory()
-  var sub1 = sub(db, 'test1')
-  var sub2 = sub(db, 'test2')
+  const db = factory()
+  const sub1 = sub(db, 'test1')
+  const sub2 = sub(db, 'test2')
 
   sub1.once('open', function () {
-    var stream = multileveldown.server(sub1)
-    var client = multileveldown.client()
+    const stream = multileveldown.server(sub1)
+    const client = multileveldown.client()
 
     stream.pipe(client.createRpcStream()).pipe(stream)
 
@@ -137,12 +137,12 @@ tape('multileveldown server on non-deferred subleveldown', function (t) {
 tape('multileveldown server on nested subleveldown', function (t) {
   t.plan(4)
 
-  var db = factory()
-  var sub1 = sub(db, 'test1')
-  var sub2 = sub(sub1, 'test2')
-  var sub3 = sub(db, 'test3')
-  var stream = multileveldown.server(sub2)
-  var client = multileveldown.client()
+  const db = factory()
+  const sub1 = sub(db, 'test1')
+  const sub2 = sub(sub1, 'test2')
+  const sub3 = sub(db, 'test3')
+  const stream = multileveldown.server(sub2)
+  const client = multileveldown.client()
 
   stream.pipe(client.createRpcStream()).pipe(stream)