diff --git a/.gitignore b/.gitignore
index 04dddc9..8ca7c71 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,11 +1,8 @@
 node_modules
-index.*.*
+.eslintcache
 *.log*
 *.result.css
-.*
 !.appveyor.yml
 !.editorconfig
 !.gitignore
-!.rollup.js
-!.tape.js
 !.github
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 004706e..fad75b6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changes to PostCSS Sass
 
+### 5.1.0 (December 28, 2023)
+
+- Updated: `dart-sass` to 1.69.5 (minor)
+- Updated: `source-map` to 0.7.4 (patch)
+
 ### 5.0.1 (March 8, 2022)
 
 - Fixes an issue with import files not being sent for processors to pick up. [#31](https://github.com/csstools/postcss-sass/pull/31)
diff --git a/README.md b/README.md
index a52d8f7..438ffec 100644
--- a/README.md
+++ b/README.md
@@ -137,7 +137,7 @@ grunt.initConfig({
 [dart-sass]: https://github.com/sass/dart-sass
 [dart-sass options]: https://github.com/sass/dart-sass#javascript-api
 [PostCSS]: https://github.com/postcss/postcss
-[PostCSS Sass]: https://github.com/jonathantneal/postcss-sass
+[PostCSS Sass]: https://github.com/csstools/postcss-sass
 [Sass]: https://github.com/sass/dart-sass
 [SCSS Parser]: https://github.com/postcss/postcss-scss
 [discord]: https://discord.gg/bUadyRwkJS
diff --git a/package.json b/package.json
index a9875cb..3b214f0 100644
--- a/package.json
+++ b/package.json
@@ -5,8 +5,8 @@
   "author": "Jonathan Neal <jonathantneal@hotmail.com>",
   "license": "CC0-1.0",
   "repository": "jonathantneal/postcss-sass",
-  "homepage": "https://github.com/jonathantneal/postcss-sass#readme",
-  "bugs": "https://github.com/jonathantneal/postcss-sass/issues",
+  "homepage": "https://github.com/csstools/postcss-sass#readme",
+  "bugs": "https://github.com/csstools/postcss-sass/issues",
   "main": "dist/index.cjs",
   "module": "dist/index.mjs",
   "exports": {
@@ -24,9 +24,9 @@
   ],
   "scripts": {
     "prepublishOnly": "npm test",
-    "pretest": "rollup -c .rollup.mjs --silent --exports 'auto'",
+    "pretest": "rollup -c rollup.mjs --silent --exports 'auto'",
     "test": "npm run test:js && npm run test:tape",
-    "test:js": "eslint **/*.mjs **/*.js --cache --ignore-path .gitignore --quiet",
+    "test:js": "eslint *.mjs src/*.mjs test/*.mjs --cache --ignore-path .gitignore --quiet",
     "test:tape": "node --test",
     "test:rewrite-expects": "REWRITE_EXPECTS=true node --test"
   },
diff --git a/rollup.mjs b/rollup.mjs
new file mode 100644
index 0000000..45a8ea3
--- /dev/null
+++ b/rollup.mjs
@@ -0,0 +1,16 @@
+import babel from '@rollup/plugin-babel';
+
+export default {
+	input: 'src/index.mjs',
+	output: [
+		{ file: 'dist/index.cjs', format: 'cjs', sourcemap: false, strict: false, exports: 'auto' },
+		{ file: 'dist/index.mjs', format: 'esm', sourcemap: false, strict: false, exports: 'auto' },
+	],
+	plugins: [
+		babel({
+			presets: [
+				['@babel/env', { modules: false, targets: { node: 12 } }],
+			],
+		}),
+	],
+};
diff --git a/src/index.js b/src/index.mjs
similarity index 100%
rename from src/index.js
rename to src/index.mjs
diff --git a/src/merge-source-maps.js b/src/merge-source-maps.mjs
similarity index 100%
rename from src/merge-source-maps.js
rename to src/merge-source-maps.mjs