If you’ve lost the original app and your Charge 3 runs fine, skip the update. If you must update, borrow an old Android phone with JBL Connect 3.2.1 APK.
The most common way to update your firmware is through the official mobile application. jbl charge 3 update
Updating your JBL Charge 3 Go to product viewer dialog for this item. If you’ve lost the original app and your