I was just perusing JIRA a bit and came across an item to upgrade to Kryo 4.0 for a performance enhancement:
https://issues.apache.org/jira/browse/TINKERPOP-2398 As I commented on that issue, which has not yet gotten a response, I believe that upgrading to Kryo 4.0 breaks binary compatibility with Kryo 3.0 which would mean we would probably need to stamp out Gryo 4.0 as a result. I'm not sure I see the need to produce another version of Gryo as we've deprecated it in Gremlin Server already and are pushing for wider use of GraphBinary as a replacement for Gryo and GraphSON for network serialization. I'm not sure where that leaves us with disk serialization but the limitation Gryo has in not working off the JVM hampers it a bit for what I think of as our current usage these days. I'm inclined to continue us on a path to full deprecation of Gryo, even for disk, in favor of GraphBinary, in which case, I don't think it's in our interest to introduce Gryo 4.0. Does anyone have any thoughts on this topic?
