One of the package's packaging files points to a website or code hoster known to have frozen contents, to be closed soon or to have already closed.
Please look for the new upstream home of the package and update the packaging accordingly.
Sites previously hosted on code.google.com and codeplex.com were offered a migration to github.com, sites previously on gitorious.org were offered a migration to gitlab.com, sites previously hosted on fedorahosted.org were offered a migration to pagure.io. You might want to look there first.
The tag is present in Lintian version
That is the most recent version we know about.
We use semantic versions.
The patch number is a commit step indicator relative to the
release tag in our Git
You can find the detection logic for this version at commit 131c0f4. For merge requests, please use the latest version in the Lintian check obsolete-sites.