Hairpins in Ipad

Are the hairpins in Ipad suppose to work? I don’t hear any volume change when I use them.

You won’t hear a difference in sustaining instruments like violins, flutes, trumpets etc., because the very basic Microsonic sounds that are used in the iPad version don’t support any MIDI controllers. You should hear a change in dynamic for successive notes written under a hairpin, e.g. for a run of notes written over the course of a gradual change in dynamics, but not over the course of individual notes.