Hello!

As far as I know, there are no changes that happened to the way of using vials to get a maxed skill trial or skill breakthrough but I also want to remind you that the chances of getting a Gold Skill drops when you already have some locked Gold Skill. All of it relies on your chances or the so-called RNG by other players, so make sure to observe and keep tabs of your spending. If you think you already spent a lot on getting a maxed skill then stop and reevaluate your situation. If you think that you've spent a lot already then better stop and take a rest rather than pursuing your urge to take chances trying to get a maxed skill or you will end up spending more than the price that would cost you if you take the fragments way. Hope you understand. Good luck and thank you.