Tente alterar o arquivo release-upgrades
no diretório /etc/update-manager
. Nesse arquivo, você pode usar a opção para atualizar para o LTS ou para o upgrade de versão normal:
sudo nano /etc/update-manager/release-upgrades
Altere o valor do prompt de lts
para normal
:
# Default behavior for the release upgrader.
[DEFAULT]
# Default prompting behavior, valid options:
#
# never - Never check for a new release.
# normal - Check to see if a new release is available. If more than one new
# release is found, the release upgrader will attempt to upgrade to
# the release that immediately succeeds the currently-running
# release.
# lts - Check to see if a new LTS release is available. The upgrader
# will attempt to upgrade to the first LTS release available after
# the currently-running one. Note that this option should not be
# used if the currently-running release is not itself an LTS
# release, since in that case the upgrader won't be able to
# determine if a newer release is available.
Prompt=normal
Salve o arquivo e saia.