How to "unlock" the "third" socket on infernal hound

i think is something wrong.
i have no idea how to do this i try with Lesser Jeweller orb and is not working. Any body can help me plz.
Can any GGG help me.

Hey,

It's tied to your level, can't say when you unlock 3rd or 4th.

I am level 74 and have 4 additional sockets FYI on the dog

At level 40, you get the first upgrade thats for sure, dunno about the rest yet. (Lvl 60 still "4link")

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aerialsy#7515 wrote:

Hey,

It's tied to your level, can't say when you unlock 3rd or 4th.

I am level 74 and have 4 additional sockets FYI on the dog

Weapon skills like autottack indeed are tied to level, but skills like fire bomb from staff or decompose from boots are tied to skill level and maximum skill level you can get is 19, so max support sockets are 4. If we could corrupt this skill into 20 lvl we could use 5 support sockets

4 slots is 75 and 5 slots is 90

On autoattack skills, not on skills granted by items