The Remote Desktop Manager icon from the taskbar gets removed at every update.
Since Windows 10, there is no more API available to manage the icon in the taskbar. It is Windows/Microsoft that is removing the icon from the taskbar. Because of this, it is almost impossible for us to control/manage the Remote Desktop Manager icon in the taskbar.
Other applications encounter the same issue as well. We are keeping it under the radar and if a fix is possible, we will implement it.
As of now, the workaround is to download the ZIP file of Remote Desktop Manager and perform the upgrade by simply deploying the content of the ZIP file inside the installation folder of Remote Desktop Manager.