Best_compression feature of ElasticSearch

I am using elasticsearch version 1.7. Will the best_compression feature work? In which version was this feature introduced?

It was introduced in Elasticsearch 2.0.

That was infact the best way to reduce disk storage for elasticsearch. If I am using verson 1.7, what's the next best alternative to reduce disk space?

The size data takes up on disk depends a lot on your mappings. Depending on what type of data and mappings you have it may be worthwhile revisiting this even though it is not a quick fix.