Public bug reported:
An unresolvable problem occurred while calculating the upgrade.
This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu
If none of this applies, then
*** This bug is a duplicate of bug 1069133 ***
https://bugs.launchpad.net/bugs/1069133
Thanks for your reply Brian. It would have been helpful for the error
to state something like "PPA's need revision" or something similar.
I'll check the link and hopefully be able to upgrade to 17.04
Have a
