APKMirror Installer supports all app file formats, including APKs, so you can safely install your apps. APKs are still popular, but the Google Play Store enforces the use of the Android App Bundles format by default for new apps. With the rise of 'bundling' and split APKs, the original APK format is no longer the default choice for some app developers. You can sideload many Android apps without using a third-party installer, but that's starting to change.