For some reason the email you get sent when you sign up for the early-access program also trips Thunderbird's scam warning feature (in addition to the form being submitted over HTTP, despite the site being served over HTTPS). I wonder if that's because the message contains the string "Hi Friend"?

Google "jetbrains dbe dmg" and it'll link you their knowledge base article with download links to the latest version. It's seriously a fantastic program!