However, it checks for updates in 24 hours intervals by default.

Here is a command for forcing an upgrade to a newer version:

TITLE Upgrade Express Generator

node .\bin\fetch.js ^
  --check-for-update      true ^
  --automatic-update      true ^
  --update-check-interval 0

PAUSE

How it works:
--check-for-update true - sets the fetch command to check for a new version
--automatic-update true - if a new version is available, the fetch command installs it (instead of only showing that it is available)
--update-check-interval 0 - sets the interval for checking for updates to 0 hours. This effectively forces the update.

Additional:
The TITLE sets the text in the CMD window. Now it shows "Upgrade Express Generator"

PAUSE at the end of the command keeps it open when finishes.

Note: Download the reattached command and put it in the Express Generator folder.