- Get a minecraft license (sorry, I don't want to deal with broken skins and additional auth)
- Install Prism Launcher (https://prismlauncher.org/)
- Download this mod pack zip: https://trash.dcnick3.me/gtnh/GT_New_Horizons_2.8.4+NNK.0_Java_17-25.zip
- Drag it into the Prism window to create the instance
- Under settings - Java, make sure you are using a 64-bit Java 25 for this instance. Install if necessary: https://www.oracle.com/java/technologies/downloads/#java25
- When in-game, make sure "Hidden Galacticraft Thermal Padding" resourcepack is enabled (under Options > Resource Packs)
Here's (a bit outdated) server map. You can also view live webmap at https://gtnh-web-map.dcnick3.me/new/

When selecting a place to settle in you would want it to be some distance from other people. Also make sure there is abundant water, clay and sand nearby, you will need a ton of those in the early game.
The server address is моя-жизнь-это-майнкрафт.dcnick3.me (217.25.227.208)
Good luck!
- Back up your previous instance directory in case something goes wrong
- Import the new version of the modpack: https://trash.dcnick3.me/gtnh/GT_New_Horizons_2.8.4+NNK.0_Java_17-25.zip
- Copy over the following items from your old instance:
resourcepacks, journeymap, saves, options.txt, visualprospecting, TCNodeTracker
- Under settings - Java, make sure you are using a 64-bit Java 25 for this instance. Install if necessary: https://www.oracle.com/java/technologies/downloads/#java25
- When in-game, make sure "Hidden Galacticraft Thermal Padding" resourcepack is enabled (under Options > Resource Packs)
GTNH official documentation regarding installation and updating: https://wiki.gtnewhorizons.com/wiki/Installing_and_Migrating (doesn't include the additional mods needed to play on this server)
- Download the new server zip
- Extract it with
7za x [zipname] -o[version]
cp -r [old]/{backups,banned-ips.json,banned-players.json,dynmap,eula.txt,Gregification!,serverutilities,startserver-java9.sh,ops.json,server.properties,visualprospecting,whitelist.json} [new]/
- ???
- PROFIT