I get an 504 error when trying to open the page. There's no changelog page for 4.0 linked on the home page, so I guess that it hasn't been created yet?

It appears so, the release is tracked here and isn't complete: https://github.com/qgis/QGIS/milestone/226

https://changelog.qgis.org

That page is also down.

Even previous ones, listed on Google when searching "QGIS changelog" are all down. So it's a server error on their side most likely.

It's 2026, serving semi-static webpages should be a solved problem for at least 30 years. I'm still puzzled that HN-hug-of-death is a thing.

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