Which version of freedoom does this app use?

I recently discovered an app on the google play store that uses a version of the freedoom wad. However, by extracting the iwad from the apk, i discovered that it appears to be a very old version of the wad, and i would like to know what version it is.

Link to the app is : https://play.google.com/store/apps/details?id=com.kokak.DoomGLESTD

0.7, its in the bottom right corner of the title screen.

And if your wondering, the app runs on gzdoom 2.1.1