It would seem we have a naming incongruity there. Dr.Hirudo keeps the AmigaOS Atari emulators up to date with windows versions, however it could be that "2.3" on OS4 Depot is refering to the 2.3 version of the Amiga port (Amiga port of a 2.0x version, for example on PSP they are using version 2.0.3) or something.
The latest Windows version as far as I know is
version 2.1 (also check
THIS thread on emulator zone), and it's the same you can downolad here from Dr.Hirudo's webpage:
http://hirudov.com/amiga/Atari800.phpP.S
Dr.Hirudo does
NOT upload his stuff to OS4 depot.