query works in ES (v0.90.3) but not in any other version. Currently tried on (v1.2.1)
custom_score deprecated in new versions. Use Function Score Query instead of custom_score.
The custom_score query
"custom_score": {"params": { "param1": 2, "param2": 3.1},"query": {...},"script": "_score * doc['my_numeric_field'].value / pow(param1, param2)"}becomes
"function_score": {"boost_mode": "replace","query": {...},"script_score": { "params": { "param1": 2, "param2": 3.1 }, "script": "_score * doc['my_numeric_field'].value / pow(param1, param2)"}}