teamviewer update to version 15

Hello Dears,

I need to do inplace upgrade for teamviewer to latest version (14 to 15). Some of clients installed .exe package manually and i need to install  teamviewer full msi packagei silently. Is there anyway to detect that teamviewer was installed even it is .exe package. moreover, can i install it successfully in this case? or i need to reinstall it.

Kind Regards,

Yasmeen