With some help from the PEG, I have been putting together a brief history of Progress versions and when various important features were introduced The current list follows and will be maintained at OE Hive here http://www.oehive.org/VersionHistory . There are clearly still some open questions like when DOM and the SAX options were added, but keep the input coming and I will keep updating for additions and corrections.
1984 2.1
1984 2.2 R-code
1985 3.0 Overlapping frames, ON & Apply, COLOR
1987 4.0 Workfiles, CHOOSE
1988 5.0 Fastrack, Client/Server, SQL89, federated DBs, EDITING
1989 6.0 DataServers, Parameters, RESULTS report writer
1991 6.3 APW, On-line backup
1991 7.0 GUI, E-D model, TT, UIB, DLL calls, Internal Procedures, word indexes, ReportBuilder
1993 7.2 UIB, ODBC
1994 7.3A PP
1995 7.3B
1995 7.3C
1995 8.0A SO/ADM
1996 8.0B spin, directio
1996 8.1A
1997 Webspeed 1.0
1997 7.3E
1997 8.2A AppServer (state aware and state reset), UDF, VST, DB block size
1997 8.2B
1998 Webspeed 2.0
1998 8.2C
1998 8.3A bistall/bithold, more VST
1999 8.3B rereadnolock
1998 9.0A ADM2, PUB/SUB, AppBuilder, dynamic queries, Async Appserver, stateless mode, OpenClient, type I storage areas, DOM XML parsing
1999 9.0B
1999 9.1A Integrated ABL & Webspeed, dynamic TT, Dynamics, 1st large file support
2000 8.3C
2000 9.1B SQL92
2001 8.3D
2001 9.1C
2002 9.1D new debugger, WinXP appearance, SAX reader
2003 10.0A Webservices IN, state-free AppServer, ProDataSets, Type II Storage areas, SAX writer
2004 9.1E
2004 10.0B Webservices OUT, ttmarshal, encryption, XML parsing, DateTime
2005 10.1A OOABL
2007 10.1B Major removing of limits on DB, double colon notation, 64 bit datatypes
2008 10.1C Client stack trace VST
2009 10.2A ABL GUI for .NET, Windows 64bit
2009 OpenEdge Explorer