Proposal on how to write notes on maintaining a technology stack.
If you have ever tried to refactor an already existing structure, depending on the existing materials and processes available, we would choose a specific path of upgradation. May be choosing a material of similar color, texture, or an entirely novel material which serves the purpose.
Although, it is possible for the maintainer to take a best course of action - they would sometimes like to have an opinion of the team who designed the overall structure in the beginning. Whether to take the comments provided by the initial designer is at the maintainer's understanding and judgement as per present conditions and the future goals. Wouldn't it be better if the initial designer also provides a course of action for the future upgrade, maintenance, flaws/shortcomings of the initial design, sometimes they can provide why they chose a certain material/process, and any preferences that the initial designer inclined towards.
A formal specification type document would be restrictive and forceful - actually, this kind of information is already present in the formal specifications and documentation. The purpose of the future note should be conversational, more like a commentary on formal terminology. It should be non-binding in the contractual terms in order to give the maintainer the freedom to pursue their method, while keeping the initial designers' thoughts in mind.
Here is an example of a future note.