There are newer version available. HBase for example depends on the 3.5.9.
Latest 3.5 is 3.5.11, there is the 3.6.3 as well.
While there is no point in trying to have exactly the same version, things are more comfortable if the gap in version is minimal, as the dependency is client side as well (i.e. HBase has to choose a version anyway).
Attached a patch for the branch 2.
I haven't executed the unit tests, but HBase works ok with Hadoop on Netty 3.5.9.