migration from Kerberos 4 to Kerberos 5

[paul b]

Hello,
I have a few questions about migration to a new Kerberos version. In
fact, the goal is to migrate a network with Kerberos 4 to the Kerberos
5(under Lin8x):

1) Do I have to reinstall Kerberos from the scratch or are there
packages that allow to update the version?

2) What about the users that I created, are they still valid or will
user information be lost. Part of the network uses already an LDAP
directory, do I suppose this will not be a problem for this part, but
in general, how can I migrate my user-accounts to the new version?

3) What about the clients, do I have to re-install the Kerberos-client
on each workstation or can I use the "old" Kerberos clients?

Could anybody answer my questions and perhaps give me some good hints
for the migration respectively point me to some good documents?


Thanx,
CB