LifterLMS 4.0 is a performance release so your WordPress LMS website will work faster and better at scale.
It’s a major release in that it includes backwards incompatible changes where technical debt was resolved.
Essentially a lot of old code and no longer used functiones have been removed from the codebase.
If you want to dive deep into the details of the code upgrade check out the technical LifterLMS 4.0 release post here.
Do not fear the release.
We have received precisely zero support requests related to LifterLMS 4.0.
All recommended third party plugin and theme integrations and the LifterLMS experts were notified during the 4.0 beta period and invited to review and test.
Update to 4.0 when convenient and enjoy the speed and performance enhancements on your LifterLMS powered WordPress LMS website!