This is a one-off notice, so if you've dismissed it, it shouldn't appear for anyone else. Let me know if it does. If there's ever anything else in the future, I'm assuming as the admin you will be installing the new plugin version, and you will be able to dismiss any notices before anyone sees them?
Of course, if you check the code you'll find the
add_action that you can remove if you really want to.
However, I'd advise against this. Any notices output like this will be important things for admins to read. If there's an upgrade in the future that unfortunately includes changes that may be a problem for some installations, this is how admins will be made aware of the necessary steps to avoid problems. If you remove the admin notices action, you might miss an important notice, and end up with something not working! It's a remote possibility, and of course I'm doing my best to avoid changes that might cause problems, but if it's necessary, I will include a notice with a fix.
Admins should install upgrades, of course. So, admins should see these notices on upgrading, if there are any - they need to. And they can dismiss them straight away if there's no problem - and no one else sees the notice.
Again, let me know if this isn't working properly.