Your Kobo is running an updated firmware/database version. As calibre does not know about this updated firmware, database editing is disabled, to prevent corruption. You can still send books to your Kobo with calibre, but deleting books and managing collections is disabled. If you are willing to experiment and know how to reset your Kobo to Factory defaults, you can override this check by right clicking the device icon in calibre and selecting "Configure this device" and then the "Attempt to support newer firmware" option. Doing so may require you to perform a factory reset of your Kobo.
Device database version: 149.
Device firmware version: (4, 13, 12638)
My Kobo have NOT been Jail broken or Altered ... That's what another thread in Kobo Forums said caused this problem/s
Now What?
