Trying to follow the current directions at https://docs.opendatakit.org/odk2/sync-endpoint/, the build for sync-endpoint-docker-swarm failed because it could not download sync-endpoint-war-2.1.0.pom or sync-endpoint-war-2.1.0.war from https://repo.maven.apache.org/maven2/org/opendatakit/sync-endpoint-war/2.1.0/
Thank you for pointing this out. There was a typo so it was looking for version 2.1.0 instead of 2.1.1. Please try again and thank you for your patience.