This field (modified_subnode) has caused so much performance issues in the past, and should not be part of API, as stated by @<Gaetano Giunta> in #EZP-16340 this should be loaded lazily using a a dedicated function that does a SQL MAX() query, and not have to updated on every insert.

So:

• Remove from API (modifiedSubLocationDate), SPI (modifiedSubLocation) and REST, but verify that it is set in legacy storage engine internally

Follow up step (when needed), add a function in SPI and API to get the mentioned info.