Comment 7 for bug 1924951

The dialog which follows is the final question before the upgrade actually begins. If you choose N here your system will be restored to its previous state.

Calculating the changes

Do you want to start the upgrade?

3 installed packages are no longer supported by Canonical. You can
still get support from the community.

16 packages are going to be removed. 322 new packages are going to be
installed. 1391 packages are going to be upgraded.

You have to download a total of 1,156 M. This download will take
about 2 minutes with your connection.

Installing the upgrade can take several hours. Once the download has
finished, the process cannot be canceled.

 Continue [yN] Details [d]