Just some feedback on my NW5.1 to NW6 and BM3.5 to BM3.7 upgrade
experience.

Started with a NW5.1 SP3 and BM3.5 SP3 server
Did an in-place upgrade to NW6 SP2 overlay - specified overwrite newer

files - no problems.
Reboot
BM Proxy, Radius came up ok - VPN broke (no VPTUNNEL.NLM)
Upgraded to TCP607JRev2.EXE
Reboot
Installed BM3.7 - it recognized the upgrade and proceeded as normal.
Edited PROXY.CFG file as per Craig's tip # 63
Reboot
My VPN Tunnel came back and server was functioning normally again (as
prior
to upgrade)
Tried FILTSRV MIGRATE - did not work as I could not unload IPFLT.NLM
(see
BM37SP2.TXT)
Installed BM37SP2.EXE
Reboot
Ran FILTSRV MIGRATE
As per the documentation (which I saw later), BM37SP2 replaces my
TCPIP, TCP
and BSDSOCK NLMs - re installed TCP607JRev2.EXE again.
Reboot
Installed patches for BM37FP3B.EXE, CPFILTER.NLM and NW6RCONJ2A.EXE
Applied Craig's TUNEUP.NCF file to my settings.

Everything works! Total upgrade time (not including backups - 3.5
hours).

Special thanks to all on the newsgroup (especially Craig's valuable
resources) for making this a smooth upgrade.

Cheers!

John