Otherwise the script would fail on this file:
qtlocation/src/3rdparty/mapbox-gl-native/deps/boost/1.65.1/include/boost/preprocessor/cat.hpp
Which matches this (author is not mentioned) :
Copyright (C) 2001
Error reported before the fix:
File ".../debian/scripts/update-copyright", line 114, in parse_file
if copyright[4] == '-':
IndexError: string index out of range