Can't open SW 2015 File with SW2014 SP5 / Can't mirror slot in SW2014 SP5.

I can't open SW2015 SP1.1 File on SW 2014 SP5.0

And the mirror command can't use for slot. ( SW2014 SP5 ) When i selected the slot entity and use mirror command , the center construction line is will mirrored but the shape of slot is not.

SolidworksGeneral