opendaylight-karaf-empty is only for test purpose and using Carbon version which is outdated.

<!-- dependency for opendaylight-karaf-empty for use by testing -->

<dependency>

<groupId>org.opendaylight.controller</groupId>

<artifactId>opendaylight-karaf-empty</artifactId>

<type>zip</type>

</dependency>

based on https://mvnrepository.com/artifact/org.opendaylight.controller/opendaylight-karaf-empty

it has not been updated since 2018.