diff --git a/META-INF/services/org.adrianvictor.lib.versioning.VersionedServiceRegistrar b/META-INF/services/org.adrianvictor.lib.versioning.VersionedServiceRegistrar
new file mode 100644
index 0000000..8f5e531
--- /dev/null
+++ b/META-INF/services/org.adrianvictor.lib.versioning.VersionedServiceRegistrar
@@ -0,0 +1 @@
+org.adrianvictor.lib.impl.r1_21.R1_21Registrar
\ No newline at end of file