By utilizing upgrade stones, you can further improve your equipment by enhancing its core stats, such as attack, armor and defense. There is a type of upgrade stone for each equipment category, with them being weapons, body armor and off-hand. Upon succeeding an upgrade, your equipment will have a number modifier next to its name, like this: . The higher that number modifier goes, the harder it is to succeed an upgrade, meaning that at higher upgrade levels it is more likely that you will need to spend more upgrade stones in order to successfully raise the upgrade level. Every 10 upgrade levels will require a new crystal tier.
Below, a chart was designed to better explain this system:
Whenever you obtain a better piece of equipment or weapon, you will be able to transfer your upgrades on your current weapon to the better one with some specific items, bought from Evopolis Trader located east from depot, so do not be afraid to upgrade your gear as soon as you get the stones!
This NPC will sell you the items that you need in order to transfer upgrades. Below a list was organized to better explain these items:
In order to use these absorbers, you just need to right click on them and left click on the correct gear piece with the upgrades and then repeat the process at the desired gear piece you want to transfer your upgrades to.