Hi,
Thanks for your feedback.
There 2 ways to update our theme:
1- Back-up all customization files including your changed files and language files. After that, delete the current version from WordPress then Upload the newest version which you can download from ThemeForest market. After updating, please override the change again.
2- Install Child Theme then writes all customization files and language files to it. Because Child Theme will help you to keep your change when you update our theme. After that, go to Dashboard> Update then update our theme. In some cases, you don't see the updated notification, you can update it manually.
Please check, then feedback us.
Thank you.
NooTheme