I make a Google search on Sakai forums, hoping to find a StackExchange sister site for Sakai, but there's nothing useful for me. My search keywords are sakai ~forum ~support ~offficial
I love StackOverflow and would love to have similar forum for Sakai. If you know where to ask such Sakai usage questions, e.g. "how to update questions for published multiple-choices quiz in Sakai", please share.
Thank you.
You can always post like you did here (on stackoverflow with a "sakai" tag) but we have official mailing lists as well. You can find the dev list here: https://groups.google.com/a/apereo.org/forum/#!forum/sakai-dev
For questions like your example, you probably want the user forum: https://groups.google.com/a/apereo.org/forum/#!forum/sakai-user
Or the related wiki space: https://confluence.sakaiproject.org/display/USER/Using+Sakai
There is more information on the project wiki: https://confluence.sakaiproject.org/display/CONF/Welcome+to+the+Sakai+wiki
Finally, you can look here for more information about Sakai in general: https://www.apereo.org/Sakai