A lot of it will be useful, but obviously some features won't be available like certain overlays and various options.
It builds on 2.3 and adds various things, see:
http://suretec.org/our_docs/index.html
More general admin stuff. Read over:
http://suretec.org/our_docs/appendix-changes.html
The above links are old content, more is added now in HEAD and all will be complete for the first stable release of 2.4.x
Excellent, looks really useful. Thanks.
Toby