We are upgrading https://www.xwiki.org to the current XWiki LTS (11.10.2).
What it means in practice is that https://www.xwiki.org wikis will be read-only for two days (the 27th and 28th of January) while the upgrade is being perform on a clone after which requests to xwiki.org will transparently be switched to the new up to date servers.
We will keep you informed during this process.
We apologize for the inconvenience and thank you for you patience.