The Optimizely addon hasn't been updated to support EPiServer CMS >= 9.0.0. Is there anywhere I could get the source or submit a pull request to update it?
We are considering dropping the add-on alltogether as it's blocking upgrades.
It's ready to be updated to CMS9. Please wait it a moment to be up on feed.
Version 126.96.36.19900 supports CMS 9 and is now available from the NuGet feed: