how to update Witcher 3 on GoG

how to update Witcher 3 on GoG - Brown Broom and White Plastic Bucket

I bought Witcher 3 in a local store at the time, so I installed it through discs. I've noticed the game hasn't updated since then though. In-game it says I'm still at version 1.02, though the changelog of the GoG Galaxy program talks about version 1.08 being implemented already.

Does anybody know how I can update Witcher 3?

the-witcher-3 gog

Pictures about "how to update Witcher 3 on GoG"

how to update Witcher 3 on GoG - Close-Up Shot of Keys on a Red Surface

how to update Witcher 3 on GoG - Person Holding White and Brown Newspaper

how to update Witcher 3 on GoG - Update Lettering Text on Black Background

How To Update The Witcher 3 Wild Hunt GOG (NEW Patch 1.31 !!!) Standard Version

Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.

Images: Monica Silvestre, Miguel Á. Padriñán, Ekrulila, Anna Tarazevich