We're currently on 2.17.2 for x-content:

2.17.2 was released on July 5, 2024.

Subsequently, Jackson has added the concept of LTS versions. Also, Jackson 3.0.0 was released on late 2025 (as well as four subsequent patch versions).

The 2.21.x series is a LTS version, as will likely be the yet-to-be-released 3.1.x series (source).

Within the 2.21.x series, only 2.21.0 exists so far, it was released on January 18, 2026.

While it would be very interesting to move Elasticsearch to the 3.x series, I could see that being a larger unit of work, but in the nearer term there's probably quite a bit of value in upgrading Elasticsearch within the 2.x series to an LTS version.