HBase upgrade

Hi All,

I am using HBase in distributed mode. A number of master and regionserver
nodes are running on different machines.

Now i want to upgrade HBase version to recent stable release.

My main purpose is to upgrade HBase without shutting down whole cluster.

I want to know if on one machine i upgrade HBase and on another machines
old HBase version are running. Will it create any problem?

If i upgrade whole cluster to new HBase version then will it be consistent
with previous data?