diff --git a/site.mk b/site.mk
index b63d8d6abe8349b3258ce3219a6bca22812b2756..55bcfdf32f81060693dae9d0b7027756e032719e 100644
--- a/site.mk
+++ b/site.mk
@@ -45,7 +45,7 @@ GLUON_SITE_PACKAGES += \
 	kmod-igb
 endif
 
-DEFAULT_GLUON_RELEASE := 1.0+$(shell date '+%Y.%m.%d')-g.$(shell git -C $(GLUONDIR) log --pretty=format:'%h' -n 1)-s.$(shell git -C $(GLUONDIR)/site log --pretty=format:'%h' -n 1)
+DEFAULT_GLUON_RELEASE := 1.0+$(shell date '+%Y-%m-%d')-g.$(shell git -C $(GLUONDIR) log --pretty=format:'%h' -n 1)-s.$(shell git -C $(GLUONDIR)/site log --pretty=format:'%h' -n 1)
 
 GLUON_LANGS := de en