Time to live alternative in complex scenario

In an application with around 10 million documents I have a problem around TTL - which is deprecated. The indexing application receives updates every day - which should replace any old version of the same document. Some document are updated daily, some weekly and some monthly.
The problem is that if updates to a document is not received in a period of time, the document should be removed, so it is no longer available for search - a perfect scenario for TTL - but since it is deprecated I have to find another solution.

2-3 million document are received daily within a short period of time, so batch indexing is needed - currently solved by using custom document id, making inserts of the same document overwrite the old version of the document.

Does anyone have a good idea on how to solve this..?