This small mod simply Makes vanilla upscalling upcale enemies further beyond your level
Default version upscales all enemies which were lower level than you by 6 more levels than your current level to make them fall into deadly catagory(Which allows them to get ridiculous damage and health buffs)

Its specially useful late-game when you are running NG+ ursine armor with strong attacks and 2 shotting everything even with upscaling ON.

now the game should be a little bit more challenging

of course in order to scale like this you need to have Upscaling ON in witcher 3 gameplay options.

you can also modify some simple value of ....\modChallengingUpscaling\content\scripts\game\npc\npc.ws to better suit the leveling to your liking(see the screen shot on which 3 values to edit)

Mod was made and tested in witcher 3 v1.31 GOTY steam

if you have script compilation error use script merger to automatically fix it

ADDED V2 : Will also upscale Bosses(Quest and Witcher Contracts !) further beyond your level(by adding buffs when upscale is on).The default Version will upscale bosses accordingly to keep in balanced with +6 levels of mobs(bosses dont have levels so adding balanced multiplier buffs is the only way).

Also the Multiplier buff can be modded by editing npc.ws(chaning a single value,default is 1) as well just like previous time(See screenshot and commented out // instructions)