Problems upgrading from 2.81 --> 3.10?

Hi,

I've been conversing with Paul Chapin, the UNIX admin at Amherst, about 
upgrading from procmail 2.81 to 3.10 on the Amherst UNIX machines. The 
one concern we have is this:

Will upgrading from 2.81 to 3.10 break any current .procmailrc files in 
use? Has the .rc format changed enough/any from 2.81 that it will cause 
catastrophic problems (or any problems) with current users?

Thanks for your time.

Michael Handler

(PS please cc: us both in any replies. thanks.)