...The Interplanetary Overlay Network (ION) software distribution implements Delay-Tolerant Networking (DTN) architecture, as described in Internet RFC 9171. It is designed for use in embedded environments, including spacecraft flight computers and ground systems.
ION 4.1.3s is the last version to provide both BPv7 and v6.
Starting ION 4.1.4, only BPv7 code will be available.