After activating the Modern Events Calendar Pro license, you can proceed with the following instruction to enable auto-update.
You should go to WordPress Admin Dashboard > Updates and if there is any updates you can hit the update button to get the latest version of the plugin installed automatically on your website.
Note: If you didn’t get an update notification, click Check Again.
After 15 to 20 seconds, you will get a the latest version of MEC, like the example in the image below:
Please watch the following video: