Thank you for posting it in their forums as well. I posted here hoping that someone from Larian would maybe see it and contact GOG directly to expedite the change. Guess that didn't happen so far and people using the offline installers will now run the risk of ruining their games over the weekend as GOG usually doesn't make any changes during weekends. For people pointing to GOG Galaxy: This is a nice extra for people who prefer an additional client software. GOG keeps emphasizing that GOG Galaxy is strictly optional and customers using the offline installers shouldn't be treated as an afterthought by GOG. It's already bad that we are usually last to get access to new patches but now we are also left with a game version that is known to make save-games unusable.
