HALion Sonic 7 is the new free-of-charge replacement for HALion Sonic SE 3 and is supposed to be a drop-in replacement for HALion Sonic SE 3, at least in Steinberg hosts. As Dorico uses the same sound engine as Cubase and Nuendo, I hope it will work the same as the behaviour @Philippe_Bono describes in that post for Cubase and Nuendo.
The product formerly known as HALion Sonic is now called HALion Sonic Collection - essentially, that is all the content of HALion but without the added features of the HALion instrument.
HALion Sonic Collection 7, HALion 7 and Absolute 6 are available as paid updates for existing owners.