The documentation for 4.0x refers to /cache/modules.php, could someone please verify that the reference is correct?
This release was developed solely on 4.1.x, so verification that the 4.0.x instructions are correct would be greatly appreciated
Additionally, hopefully you'll all notice that under the Administration -> Modules section, you'll now be able to Enable/Disable XC SEO, and additionally configure options for the module (currently only 1 option is presented, but there will be more added going forward).
Cheers
EDIT: something that was forgotten in the documentation, if you're upgrading, you can delete the following files (after you install the NEW release)
/seo.php
/include/templater/plugins/outputfilter.seo.php