Freemium (free 1 year) version with clamav. Premium with Add-On Avira uses Avira engine.
Version 4 is still worth using without clamav, but with other anti-viruses (Windows Defender, example). imho
Version 5 beta (or when it will be final) can probably use without other antiviruses. I take an active part in testing, APEX (offline engine by SecureAplus) is interesting and I'm glad that they took up their engine and is glad that he uses artificial intelligence, but its level of detection would be worth improving (educating).