No there are no deal breakers. We'll accept PRs and I'll release bug fixes, but no new work will be done on 1.x. We've been running it successfully for a long time, and it's become pretty stable. It was only redesigned to address issues we've seen in pretty large clusters, e.g. 7 nodes with 7 partitions (separate Atomix clusters running on the same nodes). When the cluster is put under that much stress we see architectural flaws that shouldn't be evident in simpler clusters. Atomix 2.x is also adopting much of the work we've done on top of Atomix (messaging, partitioning, cluster management, better primitives, etc). So, Atomix 1.x will always have a lot fewer features, but it's still solid and there's nothing fundamentally wrong with it.