Looking for basic, Calibre-compatible, e-ink reader

My old Kindle is getting a little long in the tooth, so I was hoping to get a suggestion for a replacement. I don't want anything fancy, just a simple e-ink reader that works well with Calibre.

My needs are pretty simple

• E-Ink only
• Decent Battery life
• Works well with Calibre - I was hoping for something that would automatically use the calibre categories, if that exists.

Any suggestions would be appreciated.