From the webpage:
This release is the third release of Apache Flume as an Apache top level project and is the third release that is considered ready for production use. This release is primarily a maintenance release for Flume 1.3.0, and includes several bug fixes and performance enhancements.
If you are using Flume in production, maintenance releases are important.
If you are learning Flume, why start with working around fixed bugs? Use the latest stable release.