The last version for Amiga is 4.3
I just bought a copy from Newtek. $19.95 for the CD, another $19.95 for the install floppy. You need both. Kinda steep for a floppy, but balanced by the cheap price of the CD I guess, for a total of $39.90 for the pair.
Do you have a Flyer? Some verions of the Flyer only work correctly with 4.3. Other Flyers work with any version of 4.x., according to Newtek. To be safe it's best to have 4.3. The used Flyer I bought did not work with the 4.1 version I already had.
Plaz