From the Hadop Core Mailing List .. :
Release 0.19.1 fixes many critical bugs in 0.19.0, including ***some data loss issues***. The release also introduces an ***incompatible change*** by disabling the file append API (HADOOP-5224) until it can be stabilized.
For Hadoop release details and downloads, visit:
Hadoop 0.19.1 Release Notes are at
Thanks to all who contributed to this release!