what files from $privatedir do I need to keep when upgrading from 221a to 222?

[Dragos]

hello everybody,

I'm planning a quick upgrade from 2.2.1a to 2.2.2, and I want to know which 
files from $PRIVATEDIR (and others) I need to keep...
I have it like this:

-rw-r--r--    1 root     root           42 Jul 28 16:40 MACHINE.SID
-rw-------    1 root     root         8192 Nov  2 12:55 secrets.tdb
-rw-------    1 root     root        10274 Nov  2 12:56 smbpasswd
I'm sure MACHINE.SID and smbpasswd must be kept, but what about secrets.tdb?
also, what about the files in $LOCKDIR (/usr/local/samba/var/locks)?
must I change them?

thanks, dragos