Here is a brief time line of the models released by Wadia.  The current models are also listed here.

Model Date Upgrades Upgrades
  Introduced   Still Available
381 CD Player 2009 yes to 381i yes
922 mono Decoding Computer 2009 yes to sc yes 
170iTransport 2008 no  
781i CD Player 2008 no  
521 Decoding Computer 2007 no  
581ise CD Player 2007 yes to 781i yes
581i CD Player 2006 yes to 'se' yes
581 CD Player 2006 yes to 'i' & 'se' yes
931 Digital Controller 2005 no  
921 mono Decoding Computer 2005 yes yes
861se CD Player 2003 no  
861b (basic) CD Player 2002 yes to 'se' no
302 CD Player 2002 yes to 'i' no
301 CD Player 2000 yes to 'i' & 'p' yes - 'p' only
861 CD Player 1999 no  
830 CD Player 1998 yes to 'i' & 'p' yes - 'p' only
270 Transport 1998 no  
850 CD Player 1997 no  
860 CD Player 1997 yes to 1 no
27 Decoding Computer 1997 yes no
20 Transport 1996 no  
25 Decoding Computer 1996 no  
16 CD Player 1995 yes no
22 Transport 1995 no  
26 Decoding Computer 1995 no  
23 CD Player 1995 no  
21 CD Player 1995 yes no
17 Analog to Digital Converter 1995 no  
12 Decoding Computer 1994 no  
8 Transport 1993 no  
15 Decoding Computer 1993 no  
6 CD Player 1992 yes no
7 Transport 1992 no  
10 Interface 1992 no  
9 Decoding Computer 1992 no  
3200T Transport 1991 no  
X32 Decoding Computer 1991 no  
2000T Transport 1990 yes no
Wadia Pro Decoding Computer 1990 no  
4000 pro Analog to Digital Converter 1990 no  
1000/64.4 Decoding Computer 1988 yes no
2000 Decoding Computer 1988 yes no