I think that I solved the problem. At the same time the Joomla update came I also updated PHP to 7.2 now I set that one step back to 7.1 and it seems the problem is over.

Hey Eric,

It seems like that PHP warning is pointing to this file JoomlaFolder/plugins/system/helix3/core/classes/menu.php , and this file is not we wrote one, it might be one of your existing template who using this helix3.

For your information, Vanilla template helix plugin is under this JoomlaFolder/plugins/system/vanillahelix3/core/classes/menu.php file location.

By the way, thanks for letting us know that error no longer exist now.

Hi Arlex,

Thank you for your reply. I am using Vanilla but never downloaded anything from Helix directly. I checked your suggestion about the place where to find the Helix template (helix3) and the place where Vanilla should be (vanillahelix3) but that last one isn't in JoomlaFolder/plugins/system/vanillahelix3/core/classes/menu.php There is only a tmp_vanilla folder there.

Does this mean that something went wrong with installing the Vanilla template?

After check further again, it seems like you still using older version of Vanilla template and the older version is rely on this file JoomlaFolder/plugins/system/helix3/core/classes/menu.php, after that we noticed there got conflict if the site got install another helix template, so we rename that plugin name to vanillahelix3 to prevent these conflict.

By the way, keep us update if those warning still persists, so we can better have a check.

Hi Arlex,

Thank you for your explanation.
Is it smart for me to download the Vanilla template again and reinstall it? And if so, will all my setting stay the same or have I do that all over again?

Thanks for your reply.
Best Regards
Eric

Hey there,

I am really sorry for the delay of this reply as it is a weekend for us here.

Yes, it should remain those setting when you update your Vanilla template to latest version.

But it would be best is do the full backup before you proceed this update, or you can clone one of the staging site then upgrade it from there and see whether everything is work fine, if yes then only perform this update on your live site.