"Warning - preg_match(): Unknown modifier 'a'" after changing website to https


Hello everyone,

Recently I’ve changed my wordpress installation to run on https instead of http. When I reconfigured Piwik to run on https ( Intention: I want the tracking code to be loaded via https too in order to avoid broken content warnings …) I ran into a couple of warnings which occupy my Piwik interface ever since.

After changing the URL of the Website which should be tracked from http to https I always have warnings of the type

WARNING: /home/.sites/4/site2156/web/analytics/core/Url.php(252): Warning - preg_match(): Unknown modifier 'a' - Piwik 2.13.1 - Please report this message in the Piwik forums: http://forum.piwik.org (please do a search first as it might have been reported already)

on every Piwik site.

Do you have any idea what might have caused the problem and how I could get rid of those warning messages?

Best regards, Alex

(Matthieu Aubry) #2

If you close these notifications, do they re-appear again and again? if so, please create a bug report at: Issues · matomo-org/piwik · GitHub



If I close the notification they do reappear the next time I reload the page or browse to another page. It’s also worth noting that they the number of them is varying.

Best regards, Alex

(Matthieu Aubry) #4

Hi Alex,

Thanks for the report. I’ve fixed the bug in: Warning - preg_match(): Unknown modifier ‘a’ · Issue #8290 · matomo-org/piwik · GitHub

It is fixed in latest 2.14.0-RC4


Hi Matt,

Thank you very much.

Best regards, Alex