HWE Problem

[torreydale]

firenice03 is probably correct on the linux-generic command.  It may only update within a series instead of upgrading or changing to another series.  What he listed should get you to 3.13 or 4.4, depending on what you want.  Version 3.19 is at "end of life" this month, so you do have to make a move if you want to stay on a supported kernel.

I concur with the suggestion to create a Systemback restore point ahead of time.