Level 7
Apparently there is a big misunderstanding on how HitmanPro works. HitmanPro does not require antivirus engines or virus signatures to catch threats. Our product is technically very different compared to other solutions in the antivirus and antimalware industry. [..]
At the core HitmanPro is based on a forensic behavioral scan and does not work with virus signatures. Actually, this means that HitmanPro does not look for verified malware at all. [..]
Judging HitmanPro on the amount of engines sounds great, but Kaspersky and Bitdefender are not the ‘engines’ you should be talking about. [..]

Local Host

Level 21
Antivirus solutions do not target what they haven’t seen before – they are in a cat-and-mouse game and this is a fundamental difference compared to HitmanPro.
Trying to sell his product there, this is not 1999, Anti-Virus have behaviour blockers and similar tech to catch malware they never seen before.

As to answer the question, they still use BitDefender and Kaspersky signatures.