What now?

If you are already using Ubuntu Touch, remember that ports are built by volunteers, so it may take some time for the device to get a new release. Follow the development and update when the release is available.
For a more stable and up-to-date experience, check out the other devices in the list as well and get the one that best suits your needs.
Check for development builds for your device, you may want to join the forum or the Xiaomi Redmi 4X Telegram group (if available) to help test and report issues.
If you have the skills, you can update the device port to the current release yourself and share it with the community. If you need help, check the documentation or ask nicely in the porters group.
You can also install a previous release; these releases will continue to work after new releases are added, but won't get updates, new features and security fixes.

The following releases are available: 16.04 - xenial