PHP RFC: Policy release process update

Introduction

This is a policy RFC that tries to match the current policy with the process that we currently have and also clarify few details.

The policy change is composed of following items

Definition of backward compatibility (BC) and noting few cases that are not considered a BC break
Clarifying that an RFC can allow a backward compatibility (BC) break in a minor version — this already occurs in practice
Introducing a special exception for breaking ABI in a patch release in the case of a HIGH severity security issue.
Allowing build compatibility fixes in security releases.
Allowing regression fixes in exceptional cases during the fourth year of support.
Improving feature selection wording.
Explicitly allowing features to be merged without an RFC if there are no objections or RFC requests from core developers. This does not apply to user-facing engine changes (including syntax changes).

Yes / No vote requiring 2/3 Yes votes to pass.

Links to external references, discussions or RFCs

Keep this updated with features that were discussed on the mail lists.