Logstash-output-elasticssearch gem out of date

I am trying to install logstash-output-elasticsearch plugin so I can use the transport protocol.

When I run
bin/plugin install logstash-output-elasticsearch-shield
I get this error message

ERROR: Installation Aborted, message: Bundler could not find compatible versions for gem "logstash-output-elasticsearch":
In snapshot (Gemfile.lock):
logstash-output-elasticsearch (= 2.2.0)

In Gemfile:
logstash-output-elasticsearch-shield (>= 0) java depends on
logstash-output-elasticsearch (<= 0.1.9) java

logstash-output-elasticsearch (>= 0) java

Running bundle update will rebuild your snapshot from scratch, using only
the gems in your Gemfile, which may resolve the conflict.

Any suggestions?