The first public review of UBL 2.2, the successor to UBL 2.1 - ISO/IEC 19845:2015, begins February 1, 2017 and closes March 17, 2017:

https://www.oasis-open.org/news/announcements/ubl-v2-2-begins-45-day-public-review-ends-march-17th 

Last week the committee also announced the acceptance of new requirements for UBL 2.3.

Comments may be submitted to the TC by any person through the use of the OASIS TC Comment Facility at:
https://www.oasis-open.org/committees/comments/index.php?wg_abbrev=ubl