diff --git a/index.js b/index.js
index eb2dd6a..5739663 100644
--- a/index.js
+++ b/index.js
@@ -6,39 +6,39 @@ const applySourceMap = require('vinyl-sourcemaps-apply');
 const autoprefixer = require('autoprefixer');
 const postcss = require('postcss');
 
-module.exports = opts => {
-	return through.obj((file, enc, cb) => {
+module.exports = options => {
+	return through.obj((file, encoding, callback) => {
 		if (file.isNull()) {
-			cb(null, file);
+			callback(null, file);
 			return;
 		}
 
 		if (file.isStream()) {
-			cb(new PluginError('gulp-autoprefixer', 'Streaming not supported'));
+			callback(new PluginError('gulp-autoprefixer', 'Streaming not supported'));
 			return;
 		}
 
-		postcss(autoprefixer(opts)).process(file.contents.toString(), {
+		postcss(autoprefixer(options)).process(file.contents.toString(), {
 			map: file.sourceMap ? {annotation: false} : false,
 			from: file.path,
 			to: file.path
-		}).then(res => {
-			file.contents = Buffer.from(res.css);
+		}).then(result => {
+			file.contents = Buffer.from(result.css);
 
-			if (res.map && file.sourceMap) {
-				const map = res.map.toJSON();
+			if (result.map && file.sourceMap) {
+				const map = result.map.toJSON();
 				map.file = file.relative;
 				map.sources = map.sources.map(() => file.relative);
 				applySourceMap(file, map);
 			}
 
-			const warnings = res.warnings();
+			const warnings = result.warnings();
 
 			if (warnings.length > 0) {
 				fancyLog('gulp-autoprefixer:', '\n  ' + warnings.join('\n  '));
 			}
 
-			setImmediate(cb, null, file);
+			setImmediate(callback, null, file);
 		}).catch(error => {
 			const cssError = error.name === 'CssSyntaxError';
 
@@ -47,7 +47,7 @@ module.exports = opts => {
 			}
 
 			// Prevent stream unhandled exception from being suppressed by Promise
-			setImmediate(cb, new PluginError('gulp-autoprefixer', error, {
+			setImmediate(callback, new PluginError('gulp-autoprefixer', error, {
 				fileName: file.path,
 				showStack: !cssError
 			}));
diff --git a/package.json b/package.json
index 378e57f..01266ef 100644
--- a/package.json
+++ b/package.json
@@ -30,18 +30,18 @@
 		"postcss-runner"
 	],
 	"dependencies": {
-		"autoprefixer": "^9.1.3",
+		"autoprefixer": "^9.5.1",
 		"fancy-log": "^1.3.2",
 		"plugin-error": "^1.0.1",
 		"postcss": "^7.0.2",
-		"through2": "^2.0.0",
-		"vinyl-sourcemaps-apply": "^0.2.0"
+		"through2": "^3.0.1",
+		"vinyl-sourcemaps-apply": "^0.2.1"
 	},
 	"devDependencies": {
-		"ava": "*",
+		"ava": "^1.4.1",
 		"gulp-sourcemaps": "^2.6.0",
-		"p-event": "^2.1.0",
+		"p-event": "^2.3.1",
 		"vinyl": "^2.1.0",
-		"xo": "*"
+		"xo": "^0.24.0"
 	}
 }
diff --git a/test.js b/test.js
index 107abe2..0b231f7 100644
--- a/test.js
+++ b/test.js
@@ -3,10 +3,10 @@ import test from 'ava';
 import Vinyl from 'vinyl';
 import sourceMaps from 'gulp-sourcemaps';
 import pEvent from 'p-event';
-import m from '.';
+import autoprefixer from '.';
 
 test('autoprefix CSS', async t => {
-	const stream = m();
+	const stream = autoprefixer();
 	const data = pEvent(stream, 'data');
 
 	stream.end(new Vinyl({
@@ -27,7 +27,7 @@ test('generate source maps', async t => {
 	const data = pEvent(write, 'data');
 
 	init
-		.pipe(m({
+		.pipe(autoprefixer({
 			browsers: ['Firefox ESR']
 		}))
 		.pipe(write);
@@ -41,7 +41,7 @@ test('generate source maps', async t => {
 	}));
 
 	const file = await data;
-	t.is(file.sourceMap.mappings, 'AAAA;CACC,cAAc;CACd');
+	t.is(file.sourceMap.mappings, 'AAAA;CACC,aAAa;AACd');
 	const contents = file.contents.toString();
 	t.true(/flex/.test(contents));
 	t.true(/sourceMappingURL=data:application\/json;charset=utf8;base64/.test(contents));
@@ -49,7 +49,7 @@ test('generate source maps', async t => {
 
 test('read upstream source maps', async t => {
 	let testFile;
-	const stream = m();
+	const stream = autoprefixer();
 	const write = sourceMaps.write();
 	const sourcesContent = [
 		'a {\n  display: flex;\n}\n',