2026 support is only coming out in Corona 12 Update 2 (since it’s due for release in a couple of weeks, it didn’t make sense to do a hotfix). It is in the daily build for testing though, so you can use that in the meantime (which will be necessary to confirm 2026 is working without problems), see https://forum.corona-renderer.com/ Chaos Corona 13 for 3ds Max - Daily Builds Changelog #msg232441