[Internal]: Update entity store docs with the supported new features and limitations

[uri-weisman]

Description

What’s new for 9.2:
1. Historical views – We now capture daily snapshots of the entity store, allowing users to query past states and build trendlines over time.
2. CRUD API – Starting in 9.2, a new API is available for interacting with the entity store. In this release, the supported operation is UPSERT (create + update).

Important note we should add for existing users:
Clients who installed the entity store before 9.2 will need to reset the store (by toggling the button) in order to access these new features, this is due to technical limitations.

Resources

Historical Views:

• https://github.com/elastic/entity-store-docs/blob/592ce43d2525b67614ae75a48aa56d4d2559d3b0/architecture/0001-entity-store-history-snapshots.md

CRUD API:

• Product Epic
• Implementation

Which documentation set does this change impact?

Elastic On-Prem and Cloud (all)

Feature differences

For serverless no ILM policies will be apply as it's not supported.

What release is this request related to?

9.2

Serverless release

The week of September 23, 2025

Collaboration model

The documentation team

Point of contact.

Main contact: @uri-weisman

Stakeholders: @MikePaquette