See this post on phpbb.com for details.
This version of the extension can be downloaded from my digest extension page or from the GitHub 3.2.8 branch page. When downloading from GitHub, remember that it must be copied into a blank /ext/phpbbservices/digests folder.
Of course disable the current digest extension first then remove the /ext/phpbbservices/digests/* files. Then upload the new version then enable again.