Handle major version upgrades

[autholykos]

Describe "Why" this is needed
Upon breaking changes, we need to ease for the end user any eventual procedure (which might be automated) in upgrading the software.

Describe alternatives you've considered
A suitable implementation would foresee a generic template in the code, to be filled by the developer in case of the breaking change. In its simplest form, in case of required manual procedures, a panic with a detailed description of what to do would probably suffice.

Additional context
This is a first step in handling a node's upgrade.