[j-nsp] trying to upgrade OS on M5, getting "not compatible" error

[sthaug at nethelp.no]

> These messages are somewhat common when you skip a few releases. When
> wearing my **testing** hat I use the "force" option, and when available
> the "no-validate" switch, to make things happen when I see such
> messages. I generally have success with this, especially when upgrading.
> Sometimes on a downgrade your config will not be committed due to
> unsupported statements. In some cases the release notes will inform that
> you have to upgrade/downgrade to some intermediate version, but in the
> case of 7.6R4.3 I saw no such instructions.

We used to "no-validate" option when upgrading from 7.6-20061012.0
(interim release) to 8.1R2.4 on several boxes. On one particular box
we were bitten by this practice: We had one route distinguisher with
an extra digit which made it syntactically incorrect. 7.6-20061012.0
accepted the RD, 8.1R2.4 did not. The result was a box which needed
console port access to finish the upgrade - and we consider this
entirely our own fault.

> I believe that the "validate" option is the default when moving between
> releases, and the 5.6 release does not seem to offer no-validate as a
> choice.

We certainly have the experience that "validate" is the default yes.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no