Currently Drill uses 2.7.4 version of hadoop libraries (hadoop-common, hadoop-hdfs, hadoop-annotations, hadoop-aws, hadoop-yarn-api, hadoop-client, hadoop-yarn-client).
A year ago the Hadoop 3.0 was released and recently it was updated to Hadoop 3.2.0.
To use Drill under Hadoop3.0 distribution we need this upgrade. Also the newer version includes new features, which can be useful for Drill.
This upgrade is also needed to leverage the newest version of Zookeeper libraries and Hive 3.1 version.