The versions of the Proton pom files were changed on master yesterday to 0.10-SNAPSHOT (i.e <next-release>-SNAPSHOT), from their previous constant use of 1.0-SNAPSHOT regardless of the next release version. As a result of this the nightly snapshot job is now publishing with the new version, which means there are currently stale artifiacts in the snapshot repo with the previous version. If you want current snapshots you need to update your dependencies accordingly.
I decided to raise a JIRA to request INFRA nuke the stale artifacts. In doing so I went through all the published org.apache.qpid.* artifacts and found a significant number of stale versions or artifact names from the past, so I have asked for all of those to be removed as well: https://issues.apache.org/jira/browse/INFRA-9561 Given the extent of the mess we have made, its possible the best way forward could be for infra to simply delete everything and then we republish current snapshots. That would create a small window where no snapshot is available when requested, so I'll send an update if that is how things proceed. Robbie