DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.
The welcome banner changed from "Welcome to Opus 4.7 xhigh! · /effort to tune speed vs. intelligence" to "Opus 4.7 xhigh is now available!" with separate effort and model hints.
Evidence
Welcome message (search for "Opus 4.7 xhigh is now available") — Vy1 at line ~514278
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Related
Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.