diff --git a/dev-ml/zarith/zarith-1.3.ebuild b/dev-ml/zarith/zarith-1.3-r1.ebuild
similarity index 98%
rename from dev-ml/zarith/zarith-1.3.ebuild
rename to dev-ml/zarith/zarith-1.3-r1.ebuild
index a0355294faf6e..91bc43d104fdc 100644
--- a/dev-ml/zarith/zarith-1.3.ebuild
+++ b/dev-ml/zarith/zarith-1.3-r1.ebuild
@@ -11,7 +11,7 @@ HOMEPAGE="https://forge.ocamlcore.org/projects/zarith/"
 SRC_URI="https://forge.ocamlcore.org/frs/download.php/1471/${P}.tgz"
 
 LICENSE="LGPL-2.1-with-linking-exception"
-SLOT="0"
+SLOT="0/${PV}"
 KEYWORDS="~amd64"
 IUSE="doc mpir +ocamlopt"