HL2 versions

Protocol version 6
Exe version 1.0.1.0 (valve)
Exe build: 12:18:31 Nov 2 2004 (2187)
>>>>could be a different game but the date kinda makes sense

protocol version 7
exe version 1.0.1.0 (valve)
exe build: 12:16:15 Apr 6 2006 (2707)

Protocol version 7
Exe version 1.0.1.0 (valve)
Exe build: 17:27:58 Dec  3 2009 (4044)

======================================Old / New Engine split======================================


Protocol version 15
Exe version 1.0.0.0 (hl2)
Exe build: 13:50:44 Aug 11 2010 (4295)

Protocol version 15
Exe version 1.0.0.0 (hl2)
Exe build: 13:46:47 Nov 28 2012 (5135) (220)



======================================Steampipe Beta Start======================================

Protocol version 24
Exe version 1745010 (hl2)
Exe build: 16:58:34 May 16 2013 (5304) (220)

Protocol version 24
Exe version 1745010 (hl2)
Exe build: 17:02:29 May 23 2013 (5311) (220)