You can download V10 daily build from the link below and use the new old feature in rounded edges today. Just make sure to read daily builds FAQ (available in the same link) and understood the risk of using daily builds. The most recent build is already reached release candidate state, so should be close to final in terms of features and stability.
https://forum.corona-renderer.com/ Chaos Corona 10 for 3ds Max - Daily Builds Changelog #msg213161