Referring to, "Anyone try a 5.x client with a 6.3 server?"

It is my understanding that the V6.3 server code was not designed for 
compatibility with V5 clients, and that TSM Support will limit its problem 
solving help to "best effort".

To discover the degree of incompatibility, we downgraded a V6 Linux client to 
V5.5.3, and backed it up successfully to a RHEL5 V6.3 TSM test server. We also 
downgraded a Windows V6 client to V5.5.3, and backed it up successfully to the 
RHEL5 V6.3 TSM test server. We have not tried restores yet.

About 9% of our clients were on V5. We announced the TSM server upgrade about 
six weeks ago, describing the potential incompatibility. Then, followed up by 
direct contact with the admins of the V5 clients to help them migrate to V6. 
The announcement, and the incompatibility issue, has helped motivate some 
client admins to finally retire some servers that were already moribund. There 
are about a dozen V5 clients left, but most of them belong to the 'Unix Support 
Group' who can roll with the punches.

Best wishes,
Keith Arbogast