The relevant link for LTSC version history is: https://learn.microsoft.com/en-us/windows/iot/iot-enterprise...

    Windows 11 IoT Enterprise, version 25H2  2025‑09‑30
    Windows 11 IoT Enterprise, version 24H2  2024‑10‑01
    Windows 11 IoT Enterprise, version 23H2  2023‑10‑31
    Windows 11 IoT Enterprise, version 22H2  2022‑09‑20
    Windows 11 IoT Enterprise, version 21H2  2021‑10‑04

Looks like annual versions...