Sorry @pkr1979 and @01101111 this is not a FOSS solution but you may be able to install Serif PhotoPlus under wine and use as a free workaround as I use my old paid 20 for PhotoPlus9 now on Trisquel which is based on ubuntu 16.04
Sorry @pkr1979 and @01101111 this is not a FOSS solution but you may be able to install Serif PhotoPlus under wine and use as a free workaround as I use my old paid 20 for PhotoPlus9 now on Trisquel which is based on ubuntu 16.04