Update error - opera NO_PUBKEY

[stevef]

Thank you. It seems opera have done something at their end and changed their signing key..
This is link to a post on the opera forum which describes the problem and I think describes a fix (towards the end).

https://forums.opera.com/topic/85007/dup...-not-found

You can optionally tidy up your system a little. It is reporting that there are some redundant packages which you no longer need and can be removed with the command

Code:

sudo apt autoremove

Again, you may need to enter your password and to confirm the action.