Elasticsearch Migration Plugin

I am currently running 1.7.1 and would like to upgrade to 2.1
When I am trying to use the Migration Plugin v0.16, I get a warning that I may loose data
http://localhost:9200/_plugin/migration/test_index_segments.html
warning is: "TEST INDEX SEGMENTS - THIS TEST SUITE IS DESTRUCTIVE"

http://localhost:9200/_plugin/migration/test.html
warning is: "CAUTION: THIS TEST SUITE WILL DELETE ALL YOUR DATA"

https://github.com/elastic/elasticsearch-migration

Don't run those, just run the checks under http://localhost:9200/_plugin/migration.

Thanks