Code
Write a migration guide
What broke between two versions, and the codemods to fix most of it.
Fill it in
Which project.
Which two versions.
For the mechanical ones.
Your prompt
Write a migration guide for [the library], [your from and to]. Diff the PUBLIC API semantically, not textually. What matters is what a caller has to change: removed exports, changed signatures, altered defaults and different behaviour under the same call. A changelog lists commits; a migration guide lists edits. The silent breaks are the important part. A renamed export fails loudly at build time; a changed default fails in production three weeks later, and those deserve the top of the document. Write codemods for the mechanical changes, and say what fraction they cover. Eighty percent automated with a clear list of the rest is a good migration; a codemod claiming to do everything is one nobody trusts. Order by how many callers hit it.
Use Write a migration guideOpens with everything above already filled in.
Why this works
A renamed export fails loudly at build time. A changed default fails in production three weeks later, and those silent breaks belong at the top of the document. This diffs the API semantically and writes codemods for the mechanical part.