The HAVOC: Tactical Miniature Warfare rules are now available from the One Bookshelf series of websites.
From their announcement:
I am excited to announce that I have partnered with the company that runs Wargame Vault, DriveThru RPG, and RPG Now, to to be the exclusive distributors for the digital editions of my products.
Now you will have access to the games that I create at a reduced price, you can pay in multiple currencies, with no postage costs, and best of all, you don’t have to wait.
Currently, HAVOC in available in PDF.