debian/changelog

+cluster3 (1.56-2) UNRELEASED; urgency=medium
+
+  * Use secure copyright file specification URI.
+  * Trim trailing whitespace.
+
+ -- Jelmer Vernooij <jelmer@debian.org>  Sat, 20 Oct 2018 13:52:04 +0000
+
 cluster3 (1.56-1) unstable; urgency=medium
 
   * New upstream version

debian/copyright

-Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: cluster
 Upstream-Contact:  M. J. L. de Hoon <mdehoon@ims.u-tokyo.ac.jp>
 Source: http://bonsai.hgc.jp/~mdehoon/software/cluster/