made some small addition about our BC promise and semantic versioning
feature #3644 made some small addition about our BC promise and semantic versioning (fabpot)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #3644).

Discussion
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made some small addition about our BC promise and semantic versioning

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | no
| Applies to    | all
| Fixed tickets | n/a

Commits
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a300510 made some small addition about our BC promise and semantic versioning