The engine is not historical at all. It was released in 2015 by its author Alexandru Mosoi from Romania. According to CCRL the stable version of Zurichess is rated 1728 ELO on 40m/4' time control while Appelenzer version ported by Jim Ablett is a developement version.
Last thing for the eagle eyed readers: The engine is not named Zurichchess like on the logo above but Zurichess.
You may download and try Zurichess: HERE