Maybe we can also make the error messages a bit nicer and eg say "you have to compile Piwik with --with-json | --with-hash | --with-pdo" etc. ?

👍

Maybe we can also recommend in a FAQ which flags are needed (haven't checked if there is already such a FAQ)?

We do have a "Recommended Configuration" section in the Requirements user guide - maybe this could be added there (let me know the command line and I can add it)

We can close it without doing anything if it's not worth spending time on it.

I think it's very important to make this part smooth, I see following (low effort) action items:

• the system check should be self explanatory and helps users in case anything is mis-configured. +1 to improve error messages when possible
• curious to undestand why Piwik could be installed without json (it's marked as required),
• we likely need to add hash to the list of required extensions,
• +1 to display a link to a system check on all error pages to see what is missing

FYI: In case it was not clear. I had an existing installation of Piwik and updated my PHP version. It took me quite a long time to get everything working and after some parts of the UI were working I discovered more parts that weren't working including the system check did not work even though other parts of UI were working. I think this can be quite a common scenario, especially now that maybe more will upgrade to newer PHP versions for Piwik 3.0.

@tsteur could the System check have a fallback UI that won't fail in such cases?

Yes, that would be really great. We kinda need to test the system check with no additional extension installed.

Just also noticed filter extension is required too and not mentioned in the check I think

Thank you for the report 👍 To likely fix the issue, could you upgrade to the latest Matomo version?
see https://matomo.org/docs/update/

if you still experience this issue afterwards, please re-open this and post a comment. Thanks!