2K Administrator Ron posted the following on the offical 2K forums:
Due to some upcoming things for 2K11, I wanted to let you know what past games will be affected. Here is the list of games that will be fully functional after 7/1/2010:
All 2K10 Titles
All Last Edition Titles (Top Spin 3, BIGS 2, etc.)
All Series With No Revision - NFL 2K5, APF 2K8, CH 2K8
For the discontinued 2K9 and prior 360 titles, match making and leaderboards on LIVE will still be available, but the additional features we offer (leagues, sports ticker, lobbies) will not be available.
I am unsure that this will affect any particular achievements that depend on any features beyond match making, but it would be worthwhile to try and compile a list of possibly affected achievements.
The servers are not being completely shut down, just limited to match making and leaderboards. All the frills and such are being trimmed out.
If you know of achievements that will be affected posted them in the comments section and we will update the list accordingly. Titles To Be Affectedhttp://www.trueachievements.com/College-Hoops-2K6-xbox-....htmhttp://www.trueachievements.com/College-Hoops-2K7-xbox-....htmhttp://www.trueachievements.com/MLB-2K6-xbox-360.htmhttp://www.trueachievements.com/MLB-2K7-xbox-360.htmhttp://www.trueachievements.com/MLB-2K8-xbox-360.htmhttp://www.trueachievements.com/MLB-2K9-xbox-360.htmhttp://www.trueachievements.com/NBA-2K6-xbox-360.htmhttp://www.trueachievements.com/NBA-2K7-xbox-360.htmhttp://www.trueachievements.com/NBA-2K8-xbox-360.htmhttp://www.trueachievements.com/NBA-2K8-Japan-xbox-360.htmhttp://www.trueachievements.com/NBA-2K9-xbox-360.htmhttp://www.trueachievements.com/NHL-2K6-xbox-360.htmhttp://www.trueachievements.com/NHL-2K7-xbox-360.htmhttp://www.trueachievements.com/NHL-2K8-xbox-360.htmhttp://www.trueachievements.com/NHL-2K9-xbox-360.htmhttp://www.trueachievements.com/The-BIGS-xbox-360.htmhttp://www.trueachievements.com/Top-Spin-2-xbox-360.htm