When a question or answer was posted under one license (e.g. CC BY-SA 3.0), and edited under a different license (e.g. CC BY-SA 4.0), who should be credited as the "author" for attribution purposes?
The original poster only, specifying the earlier license?
The most recent editor only, specifying the later license?
The OP and the most recent editor, specifying the earlier license for the OP and the later license for the most recent editor?
The OP and all editors, specifying the license for each of them?
From the recent Meta post on Creative Commons Licensing UI and Data Updates:
- Every time a piece of content on the site is edited, the editor creates a new version of the previous version. The new version of that work is considered to be republished and therefore governed under the CC BY-SA version in effect as of the day on which the edit was made.
- Each revision to a work creates a new version and is licensed separately. Thus current version of any piece of content (that appears on the site) is the most recent revision, and will have a license version based on the date on which that revision was published.
That kind of seems to imply Option 2 (attribute to the most recent editor only). But if so, the OP wouldn't receive any attribution for an edited post.
Option 4 would cover everyone, but it could get verbose if the post has been edited a bunch of times:
Stack Overflow question, "How do I exit the Vim editor?"
by jclancy, licensed under CC BY-SA 3.0
Edits by Andrie licensed under CC BY-SA 3.0
Edits by jclancy licensed under CC BY-SA 3.0
Edits by Andrie licensed under CC BY-SA 3.0
Edits by Cole Johnson licensed under CC BY-SA 3.0
Edits by Nick Volynkin licensed under CC BY-SA 3.0
Edits by Peter Mortensen licensed under CC BY-SA 3.0
Edits by Peter Mortensen licensed under CC BY-SA 4.0
Alternatively:
Stack Overflow question, "How do I exit the Vim editor?"
by Peter Mortensen, licensed under CC BY-SA 4.0,
based on post by Peter Mortensen licensed under CC BY-SA 3.0,
based on post by Nick Volynkin licensed under CC BY-SA 3.0,
based on post by Cole Johnson licensed under CC BY-SA 3.0,
based on post by Andrie licensed under CC BY-SA 3.0,
based on post by jclancy licensed under CC BY-SA 3.0,
based on post by Andrie licensed under CC BY-SA 3.0,
based on post by jclancy licensed under CC BY-SA 3.0
Stack Overflow, "How do I exit the Vim editor?", question by jclancy licensed under CC BY-SA 3.0; edits by Andrie, jclancy, Cole Johnson, Peter Mortensen licensed under CC BY-SA 3.0; edits by Peter Mortensen licensed under CC BY-SA 4.0
Stack Overflow, "How do I exit the Vim editor?", answer by dirvine licensed under CC BY-SA 3.0; edits by Kamil Kisiel, dirvine, Rory O'Kane, Elijah Lynn, shilovk, TankorSmash, Stefan, Kishan Rajdev, Sparhawk, Ahmad Awais, anna328p, GypsyCosmonaut, ahstro, Hauleth, woot licensed under CC BY-SA 3.0; edits by andrybak licensed under CC BY-SA 4.0