Works with 2021, 2020, and 2018 clients but does not work with 2017 client as the feature rbxfpsunlocker uses to unlock the fps was not added yet
When it asks you to update DO NOT UPDATE otherwise it won't work. I didn't remove the update check because I am lazy and this works fine. Just disable the update check after opening it.
Based on version 4.4.4 of rbxfpsunlocker.
source code is in pkfpsunlocker.zip so you can see what I did if you want as well as the compiled app because I forgot to delete it and I will not be fixing it because I am lazy.