BuddyPress.org

There is no problem.
1. Turn off everything (all plugins sites).
2. Delete bp-default and bp-sn-parent
3. Delete old buddypress
3. Install version 1.2.5. (Or 1.2.4 if you want it).
4. Install Buddypress Sitewide activity Widget plugins
5. Install BuddyPress Widget Theme 1.2.1 by modemlooper
6. Enable rest
See other plugins that are compatible with version 1.2.4. (Download the latest versions).
I have had:
– BuddyPress Group Documents
– BuddyPress Links
– BuddyPress Sitewide Featured Posts
– BuddyPress Album+
– BuddyPress Sitemap Generator
– Facestream
– FeedBurner FeedSmith
– FollowMe
– JR Favicon for WordPress
– Lightbox 2
– Post videos and photo galleries
– SPNbabble
– Tweetstream
– WP Google-buzz
I did upgrade to four sites with thousands of customers and have not had any problems.
Make it a battle plan that does not look anything changes from the old buddypress and everything goes well and is ok (you will not lose anything).