New or altered infusions are listed here.
A Homunculus Servant has a number of d4 Hit Dice equal to your level and gains a one-time bonus to its Hit Points equal to your Intelligence modifier. Due to its 12 Constitution this results in Hit Points equal to (3.5) times your level + your Intelligence modifier (rounded down, minimum 10 Hit Points).
This rules is what I expect we will want to play with at higher levels, as I think the Homunculus Servant's HP will scale too slowly. We'll see how it works out.