I have tested this SW-Synths from Superwave on a Receptor 1 with OS 1.7.
I have the shareware synths -Megabundle- registered for me. The PC is running the newest versions; the receptor the oldest versions.
All download-versions are actually found on the Superwave-Homepage http://www.superwavesynths.co.uk/downloads.htm
This SW-Synths are full functionally with the GUI: 
Freeware P8 - only V1.7
Shareware Performer - only V1.2
Shareware Professional - only V2.1
Shareware Tarkus - only V1.0
Shareware Trance Pro - only V2.1
This synths are from Megabundle too - only V1.0
This Superwave only have sounds and presets, to want loading the GUI let the Receptor short or long restart: 
Freeware Stylophone - both versions
Shareware Tinypops - old version tested
Shareware P80 - old version tested
Shareware D808 - old version tested
Shareware D909 - old version tested
This synths are from Megabundle - only V1.0
Friendly regards from
Wilfried Kuligowski, Germany