diff --git a/sci-libs/ensmallen/ensmallen-2.19.0.ebuild b/sci-libs/ensmallen/ensmallen-2.19.0-r1.ebuild
similarity index 98%
rename from sci-libs/ensmallen/ensmallen-2.19.0.ebuild
rename to sci-libs/ensmallen/ensmallen-2.19.0-r1.ebuild
index 3c3baedb60..7cc034d17c 100644
--- a/sci-libs/ensmallen/ensmallen-2.19.0.ebuild
+++ b/sci-libs/ensmallen/ensmallen-2.19.0-r1.ebuild
@@ -15,7 +15,7 @@ SRC_URI="https://github.com/mlpack/ensmallen/archive/${PV}.tar.gz -> ${P}.tar.gz
 KEYWORDS="~amd64"
 
 LICENSE="BSD"
-SLOT="0"
+SLOT="0/${PV}"
 IUSE="openmp test"
 RESTRICT="!test? ( test )"