@Peppan
Try this: go to Settings / System / Software update and see if you can find it in the list of application updates.
If not, download from internet "sony calculator 1.0.a.0.5 apk" (this is the version on xz1 and the icon looks the same as on xz2) and see if after installing it appears in your apps.
Update: Or try version 8.0.0 as it looks to the last released by Sony.
