samba - Mar 2014 - Raising domain functional level Active Directory - samba3x

Hello everyone,
I have a CentOS server (5.6) with Samba 3x (v3.5.4) configured in ADS
to authenticate with kerberos on an Active Directory domain 2008, but
currently
with "Domain functional level" in 2000. I am planning to raise the
functional level of active directory to 2008.
What are the effects on authentication? Win 2008 is compatible with
samba 3.5.4? need to re-join the domain?
Thank you in advance for any replies.

regards