From fast4x in the RiMusic Telegram channel:

Hi all, i can only say that i am very sorry and that unfortunately the project cannot continue to be a music streaming app based on YouTube.

It is unfortunate this happened to such a good FOSS music streaming app. Hopefully, someone can continue it.

To all the people who contributed to RiMusic all this time, thank you for making a great music streaming app!

As well, thank you fast4x for working hard each week to get RiMusic to where it is.