Never Delete Old Documentation
A link saved in 2029 should still show what was true in 2029.
Every minor version of these docs back to v2.0 is still published at its own URL, and none of them have been edited since release.
Because People Pin Versions
An integration written against v2.4 and still running on v2.4 needs the v2.4 documentation, not a page describing v3 with a note saying some of this may not apply. Redirecting old doc URLs to the current version is actively hostile to exactly the users who did the responsible thing.
Frozen Means Frozen
Once a version ships, its pages are read-only. Not even typo fixes. The moment you allow small edits you lose the guarantee that the page shows what was true at release, and that guarantee is the entire value.
Make the Version Obvious
Every archived page carries a persistent banner naming the version and linking to current. Without it, search sends people to a four-year-old page and they have no way of knowing.
The Cost Is Almost Nothing
Static pages, no maintenance, a few megabytes. The only real cost is search noise, solved by preferring current in ranking rather than by deleting the history.
