diff --git a/advancecomp.spec b/advancecomp.spec
index 0950637..5afeef6 100644
--- a/advancecomp.spec
+++ b/advancecomp.spec
@@ -3,14 +3,24 @@ Version:        2.1
 Release:        %autorelease
 Summary:        Recompression utilities for .png, .mng, .zip and .gz files
 
-# The bundled and forked 7z (7-Zip code) in 7z/ is under the “LGPL” license.
-# Based on https://www.7-zip.org/license.txt, and the absence of any mention of
-# license changes in https://www.7-zip.org/history.txt, 7-Zip has always been
-# licensed under LGPL-2.1-or-later, specifically; we thus assume this is the
-# intended specific license for the contents of the 7z/ directory. None of the
-# sources that would be covered by the “unRAR license restriction” or the
-# BSD-3-Clause license for LZFSE are present in this fork.
-License:        GPLv3
+# Source file headers all specify GPL-2.0-or-later (see source file headers),
+# except:
+#
+#   The bundled and forked 7z (7-Zip code) in 7z/ is under the “LGPL” license.
+#   Based on https://www.7-zip.org/license.txt, and the absence of any mention
+#   of license changes in https://www.7-zip.org/history.txt, 7-Zip has always
+#   been licensed under LGPL-2.1-or-later, specifically; we thus assume this is
+#   the intended specific license for the contents of the 7z/ directory. None
+#   of the sources that would be covered by the “unRAR license restriction” or
+#   the BSD-3-Clause license for LZFSE are present in this fork.
+#
+#   Certain build-system files, which do not contribute to the license of the
+#   binary RPM, are under other permissible licenses.
+#
+# However, in version 1.17, the COPYING file was updated to GPLv3, with a
+# changelog message (in HISTORY and elsewhere) of “Changes to GPL3.” We
+# interpret this as an overall license of GPL-3.0-only.
+License:        GPL-3.0-only AND GPL-2.0-or-later AND LGPL-2.1-or-later
 URL:            https://www.advancemame.it/
 Source0:        https://github.com/amadvance/advancecomp/releases/download/v%{version}/advancecomp-%{version}.tar.gz