After a year of drafting and discussions, TechCom is putting its proposed Architecture Principles on last call, to be adopted as official policy. This policy will apply to all engineering endeavors of the Wikimedia foundation, and is intended to guide all engineering decisions, great and small. This is a big deal, but it's not intended to be a revolution. The Architecture Principles mostly codify things that have long been established practice, or have long been agreed on to be desirable. Not by everybody, but by rough consensus. We did our best to provide opportunities for input and feedback, and tried hard to incorporate and consolidate. The Architecture Principles are a statement of value of the engineers of Wikimedia, as represented by TechCom. They mean a great deal to us. We hope you will find them useful when evaluating ideas and plans. They are intended as a guide that ensures coherence, a tool that helps us build better software together. You can find the draft at <https://www.mediawiki.org/wiki/Wikimedia_Engineering_Architecture_Principles>. You can find past discussion on the talk page, but please put any new comments on the phabricator ticket where we track the last call, as required by the RFC process: <https://phabricator.wikimedia.org/T194911>. The last call is open until April 24. If no major issues are raised and remain unresolved by that time, the draft will be accepted as policy. But keep in mind that the principles are not intended to be set in stone. They are derived from the strategic goals and product priorities, from past experience and from current constraints. When these things change, the principles should change. -- Daniel Kinzler Principal Software Engineer, Core Platform Wikimedia Foundation