How to upgrade

Do I need to do this manually?

Hi,

If you didn't do any modification with Theme core files, you can just replace e.g. your News directory with News directory from the latest version of the theme. (remember about full backup).

Are you sure there isn't an easiest way. We did some modifications

Unfortunately, there's no other way. If you do a lot of modification, you should use Child theme:
https://www.gavick.com/documentation/wo ... ld-themes/

and of course for the css moidification you can use css/override.css file and for your own function, use gavern/user.funcitons.php file, if you want to do more modifications, use Child Theme and then you can just change parent theme folder. (every files)