Mount error couldn't mount RDWR because of unsupported optional features (400)

[harve186]

I have an encrypt USB HD attached to my Cubietruck with lubuntu 14.04. When trying to mount the device I get the error message:
 couldn't mount RDWR because of unsupported optional features (400)

So I need to upgrade my mount programm or neet to upgrade to xenial. But how can I do?

 

My cubitruck is a seafile and ownload server and I don't want start with a complete new image.

 

Thansk a lot for you help