Unicode Standard Annex #31, Unicode Identifier and Pattern Syntax, will be updated for Unicode 9.0. The proposed update is now available for general public review and comment.A major change in the proposed update is the addition of a new section with recommended syntax for Unicode hashtags, also including emoji characters.
The draft also makes it clearer that XID_Start/Continue properties are preferred over ID_Start/Continue, and modifies the syntax of the definition to customization cleaner, and allow for medial-only characters in identifiers.