I have just upgraded a Phabricator instance from around November 2015 to current software. However, after performing the steps, outlined in the Upgrading Phabricator document (https://secure.phabricator.com/book/phabricator/article/upgrading), I'm seeing the following exception error message upon my attempt to access the system:
File system entity '/phabricator/phabricator/resources/sprite/manifest/main-header.json' does not exist.
It is most likely not a defect, but, perhaps, something wrong that I have done inadvertently. Regardless, I would appreciate your help ASAP, as this is a single development instance I have (I plan to convert all that to multiple Docker images and build a Docker-based CI pipeline, but haven't had a chance yet, plus I'm learning Docker in parallel).
Thank you very much in advance!