You're asking two different things now...
Do you mean (first post) the operating system?
- You haven't said what you're using - windows (xp, me, vista, 7) or os x (tiger, leopard, snow leopard, lion), linux, unix, ubuntu, etc etc
- Do you mean for RAW files or for JPGs?
Or do you (latest post) mean Lightroom?
- you know LR 2.7 is quite a way behind the current version? (ie, version 3.6)
However, the Sony a850 support was included in the LR 2.6 update, so version 2.7 is fine.