Error "Ignoring ffi-1.9.13 because its extensions are not built"

Elastic Stack Logstash
1

I am getting error while installing/ updating plugin logstash-input-beats as:
"Ignoring ffi-1.9.13 because its extensions are not built. Try: gem pristine ffi --version 1.9.13"

But when do that (gem pristine ffi --version 1.9.13), it again shows error as:
"Failed to find gems ["ffi"] = 1.9.13"

I have Logstash 2.3.4 and Filebeat 1.2.3

Please help me out.
Thanks!

2

They say it's OK to ignore it: https://github.com/elastic/logstash/issues/5642

3

thanks!!