Backward compatibility / stability of Observability documents


I would like to retrieve documents from Observability (specifically: Synthetics and APM) to present data and draw graphs in my application (similar to those in Kibana). (I can't use Kibana's APIs see, Get synthetic monitor data: how? - it gets documents from Elasticsearch in turn anyway.)

This does raise the question: are backward compatible / stable the Elasticsearch documents created by APM server / Synthetics private locations? In other words: can I rely on certain fields to exist, fields to have the same format, etc. - through major versions?