Which version of MSM is compatible with EE 2.8.1?

Question

I recently updated my EE installation to EE 2.8.1. All is well except I cannot get Multi Site Manager to work. I'm currently using MSM Version: 2.1.7 Build: 20140715 and when attempting to switch to a different site's control panel using the site dropdown within the control panel, I'm presented with the following error:

Fatal error: Call to undefined method Cp::switch_site() in /system/expressionengine/controllers/cp/sites.php on line 57.

Within each of my site's main admin.php file, I've set site_name and cp_url within the $assign_to_config array but the settings are not working.

I'm wondering if the version of MSM that I have is not usable with EE 2.8.1. Can anyone confirm this or does anyone have any insight as to why I'm receiving this error?

Answer 1

Each release of the Multi-site Manager module is only compatible with the release of ExpressionEngine it accompanied. So in your case, MSM 2.1.7, was released alongside EE 2.9.0, so it won't run with 2.8.1.

If you can't upgrade to EE 2.90 for some reason, I'd contact EllisLab to see if they can provide a compatible version of the MSM module.