With the release of the P30 and P30 Pro, the Mate 20 series is now the second-latest generation of Huawei flagships. However, it appears the OEM is still maintaining an update schedule for these devices. It has announced a new beta program for EMUI 9.1 (based on Android 9) for these phones.
https://www.notebookcheck.net/A-software-update-for-the-Huawei-Mate-20-line-is-in-the-works.417270.0.html