system call incompatibilities across releases

[steve%prd.co.uk@localhost (Steve Blinkhorn)]

Three years ago I got badly bitten trying to upgrade a remote colo
server from 1.6 to 3.0.   There were two sources of difficulty: the
first was to do with the introduction of PAM; but what really did it
was the system call incompatibility introduced that meant that 3.0
binaries would not interoperate with a 1.6 kernel, so I ended up
unable to finish the business of copying all the 3.0 files (including
pam.d) into place.   So I had to go to the server farm and install
manually.

The time has come to do another round of upgrades, so I'm
understandably concerned not to run into any similar issues.   Is
there a document somewhere that lists potential issues of this kind?
I have the impression that documentation concentrates on typical or
preferred ways of installing, configuring etc., to the exclusion of
boundary conditions, like remote upgrades to headless servers, for
which one needs to tap into the wisdom of the community.


-- 
Steve Blinkhorn <steve%prd.co.uk@localhost>