Hi - I was looking to see if anyone knows when the suppressor will be unlocked for the Alpha Jackel?

I have the Hunter Edition and upgraded to the digital deluxe.

Currently, I'm about 30 kills away from maxing out the Alpha Jackel (suppressor still locked); however, I've heard on another forum that the suppressor is "exclusively" available on some "Overkill or Stalker Upgrade;" which, I'm unable to find anywhere online to purchase/download. I just wanted to make sure I can still unlock the suppressor with maxing out the A.J.

I appreciate any feedback.

Thanks,
Andrew