After reporting on this rumor in the past, it was officially announced today that Rising Star Games is making a retail run of the 3DS hit from 2015.

Videogame publisher Rising Star Games today announced it will release a physical edition of the beloved platform adventure game Shantae and the Pirate’s Curse for Nintendo 3DS™ family systems, in the USA on September 27 and in Europe on September 30.
Developed by WayForward and published by Rising Star Games, the physical boxed edition of Shantae and the Pirate’s Curse for Nintendo 3DS™ family systems is priced £29.99/$29.99/€29.99.

If you want an idea about what kind of game Shantae & the Pirates Curse is like, feel free to watch the trailer below. We will be reviewing the game close to the release of the retail version of Pirates Curse.
https://www.youtube.com/watch?v=ZTkv8CkYhHQ
Source: Rising Star Games PR Release