How to check if value of a field has changed over time

I have two or more documents getting added to ES which may have same or different values.
Is there a way to identify the records when a value for a field has changed.
For example,
If I receive below two documents, I want to be able to select the latest record based on the updateTime field as the value for count field has changed..But if both the documents were added with same value for count field, I want to ignore that.

Any help would be greatly appreciated.

Thanks

{
"_index": "abc",
"_type": "abc",
"_id": "123",
"_version": 1,
"_score": null,
"_source": {
"name": "pqr",
"count": "1",
"updateTime": "2019-11-25T22:23:50+0000"
}

{
"_index": "abc",
"_type": "abc",
"_id": "456",
"_version": 1,
"_score": null,
"_source": {
"name": "pqr",
"count": "100",
"updateTime": "2019-11-25T22:23:45+0000"
}

Hi @jchat. I hoped this could be accomplished with a top hits aggregation and a bucket script aggregation, but I've run into a known limitation. https://github.com/elastic/kibana/issues/44294

Would you mind adding a comment to that issue specifying your need. Please be descriptive of your use case. That will help us decide how to implement this feature.