Comment 8 for bug 1776887

I'd like to test the patched kernel but I've stumbled across this error when I try to install the linux-image-unsigned package and I haven't found out how to solve it:

paulo:~/Downloads$ sudo dpkg -i linux-image-unsigned-4.15.0-23-generic_4.15.0-23.26_lp1776887_amd64.deb
dpkg: regarding linux-image-unsigned-4.15.0-23-generic_4.15.0-23.26_lp1776887_amd64.deb containing linux-image-unsigned-4.15.0-23-generic:
 linux-image-unsigned-4.15.0-23-generic conflicts with linux-image-4.15.0-23-generic
  linux-image-4.15.0-23-generic (version 4.15.0-23.25) is present and installed.

dpkg: error processing archive linux-image-unsigned-4.15.0-23-generic_4.15.0-23.26_lp1776887_amd64.deb (--install):
 conflicting packages - not installing linux-image-unsigned-4.15.0-23-generic
Errors were encountered while processing:
 linux-image-unsigned-4.15.0-23-generic_4.15.0-23.26_lp1776887_amd64.deb

I suspect I'm missing something very basic.

My current kernel image is: 4.15.0-23.25