This posts is just a friendly suggestion about the Upgrade system based on what I was thinking. (No toxic comments that wouldn't help the thread or the community pls)
My idea is to make it like the craft system.
"X" amount of stones equals to "X" level of upgrade.
0 to 1 = "X" amount of red stones (for weapons)
After maybe +9 or +10 start requiring Adv stones (purples or greens based on the gear)
10 > 11 or 14> 15 = "X" amount of purple stones
Then start increasing with the levels
Obviously after maybe +5 or +6 you will need "X" amount of white stones to perform the upgrades.
I was thinking about this system just because this way would make everybody have the same chances to get +15 after certain amount of time (based on the "X" amount of hours you dedicate to farm)
Just a suggestion, comments are open to any kind of idea about this thread.