Can be used for SecurityType (167)=OPT to identify a particular security.

Valid values vary by SecurityExchange (207):

*** REPLACED values - See Appendix 6-F: 7.Replaced values: OptAttribute(tag 206) with values in CFICode(tag 461) [Replaced in FIX 4.3] ***

Exchanges: DTB (Frankfurt), HKSE (Hong Kong), and SOFFEX (Zurich)

0-9 = single digit "version" number assigned by exchange following capital adjustments (0=current, 1=prior, 2=prior to 1, etc).