21.3 is the correct version. An older version (19 or 20) shouldn’t help.
Hi there - We just tested the main Repo URL from our guide (How to Install Diggz Xenon Kodi Build V3.2 (August 2026)) with Kodi 21.3 on our Onn 4K Plus and it worked fine. We also include alternative repo URLs that may work
Also thanks @JPM69 for testing!