Hi there,
Like other themes on ThemeForest, there're two methods to update a The Fox WordPress Theme.
Method 1: Download & install Envato Market plugin then follow instructions on plugin page.
Method 2: Update item via FTP, watch the tutorial.
Hope this helps,
WiThemes
Greeting my valued customer!
We're excited to release The Fox 3.0. We aware of compatibility may happen to you while we have a lot of customers so please be patient and help us to report your issues, we'll help you out to resolve them.
Please submit your ticket with title Fox 3.0 compatibility with your detail error message (Debug must be turned ON) and your login credentials so we can help you to check it directly & fix it faster.
Also, you should always keep a backup of your site before updating to the new version.
Kind Regards,
Cuong Tran