Occasionally, macOS users may see the following pop-up message when booting their computer, using the UAD Software or UAD Console:
Legacy System Extension – Existing software on your system loaded a system extension signed by "Universal Audio", which will be incompatible with a future version of macOS. Contact the developer for support.
You can safely ignore that message, as the UAD software is fully compatible with the currently supported versions of macOS. There are no further announcements on future OS compatibility at this time.
For more information, you can find the latest updates on OS compatibility in this article.