Hey gang, I filed HDFS-3137 so that the 0.23 releases would only support upgrades from Hadoop version 0.18 or later. People on versions before 0.18 (don't think there are many, if any, people running these) would have to upgrade to a version like 1.0 and then upgrade again from there if they wanted to move to 0.23. I think that should be fine but wanted to call it out here, give people an opportunity to chime in on the jira.
The motivation is that I'd like to do some HDFS cleanup to enable another change that would break v0.17 and earlier. Thanks, Eli
