The add-on is available for free and works with Blender 2.79 or higher.

3D Artist and Developer, known as ucupumar, has released a new add-on that should definitely help those artists who use Blender as their go-to texturing software. Meet Ucupaint, a free Blender add-on that allows its users to manage texture layers for Eevee and Cycles renderer. According to the developer, the add-on works with Blender 2.79+, but some of the more advanced features are only available on Blender 2.80 or higher.

Ucupaint locations in Blender 2.79 and Blender 2.80+:

Unfortunately, as of right now, the add-on doesn't support UDIM images and can be slow if your project has lots of layers with lots of channels.

You can learn more about the add-on here and download it for free over here.