The tag is present in Lintian version 2.109.24. That is the most recent version we know about.
The copyright file refers to the versionless symlink in
/usr/share/common-licenses for the full text of the GPL, LGPL,
or GFDL license, but the package does not appear to allow distribution
under later versions of the license. This symlink will change with each
release of a new version of the license and may therefore point to a
different version than the package is released under.
debian/copyright should instead refers to the specific version
of the license that the package references.
For example, if the package says something like "you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 dated June, 1991,"
debian/copyright file should refer to