There are two new weapons slated for this release.
The first is the Pile Driver. It is similar to like-named weapons in other Scorched Earth games like pocket tanks. Some games call it a jackhammer. When the shell hits, it bounces sever times, removing dirt each time before the final explosion. The final explosion is the largest and does the most damage.
The second isn't really a weapon. It's a transporter. It was requested by a user. To use it you shoot another player or a barrel and swap places with whatever you hit. A smart player could place an enemy right on a top of a barrel or in a pit, then finish him off.
The new weapons will come out September 23rd.