There are two mailing lists relating to SMuFL: one is for announcements only, and the other is for open discussion relating to the development of the standard.
To receive notifications by email about important developments related to SMuFL, such as the release of a new version or other major update, please subscribe to the SMuFL-announce mailing list. This is a very low traffic, read-only mailing list.
To participate in the development of SMuFL and to discuss the evolving standard with other interested parties, please subscribe to the SMuFL-discuss mailing list.
You can read past discussion on the SMuFL-discuss mailing list via Nabble.