Currently the Auto-Update only checks and downloads the setup package (interrupting user with a question before downloading). The user has to manually go through the entire setup process each time there is an update.
1. When Notepad++ is running (provided, the user has not disabled auto-update), silently download setup package in the background (if not already downloaded). Do not interrupt the user with any prompt.
2. When user closes Notepad++, inform user that an update package is ready, and ask whether to install now.
3a. If uses clicks Yes, close Notepad++ and do a fully automated upgrade installation (only show a progress to user). The user should not be required to answer any further prompts (except any failure cases) or shown a 'finished' message. Tip: You can easily achieve this using a silent installation switch in the setup program (ensuring such a switch is supported by it). When setup is run without the switch, it should show the installation wizard.
3b. If user clicks No (or Notepad++ had shut down abruptly), offer to install downloaded setup package when the user start Notepad++ next time. Again, it should be done silently as described in 3a.
The user could be given an 'Install without prompting' option in Notepad++ Auto-Update settings (let the user know about this setting when asking user whether to install). In this case, for steps 3a and 3b (3b would happen when Notepad++ was shut down abruptly), install silently without any prompts, showing only a progress bar to the user.