Hello,
Thank you for your message.
If I upgrade or buy the Pro version, this message will disappear forever from my hosts?
Yes, the notification banner is not shown when connecting to remote Hosts via Viewer registered with any commercial license (i.e. Starter, Mini, Endpoint or Pro).
In this case, using the Viewer, Can I click on the message using the Full control feature or the person who is the host clicks, only once and the message will not appear anymore?
No, the notification banner will not be displayed at all. However, you can always enable this notification banner in the
Host Settings -> on the Interface tab.
Please let us know if you have more questions.