Is it mandatory to install X-Pack on logstash in order to output to X-Pack'd Elasticsearch?

Hey Guys,
So recently I installed X-Pack on Elasticsearch and Kibana and I'm now getting an error when trying to output to Elasticsearch from Logstash.

I was wondering if X-Pack has anything to do with it, and if it does, what is required to make it work.

Thanks in advance!

Have you seen this documentation?