diff --git a/app/lib/Makefile b/app/lib/Makefile
index 9d46c69..8ba78bf 100644
--- a/app/lib/Makefile
+++ b/app/lib/Makefile
@@ -44,7 +44,7 @@ xtrkcad.lyt: mklyt
 	@./mklyt xtrkcad
 
 xtrkcad.upd:
-	( date "+%Y%m%d" ; \
+	( LC_ALL=C date --utc --date="`dpkg-parsechangelog -SDate -l../../debian/changelog`" "+%Y%m%d" ; \
 	for f in `make --no-print-director -f params/Makefile xtps` ; do \
 	echo $$f ; done ) > xtrkcad.upd