Is this a case of built in obsolesce?

My son gave me this MacBook Pro; I upgraded with 1TB SSD and new battery.  It runs perfect - it's everything I need,  and at 73 years old, my needs are significantly less than others needs may be.  

I am attempting to install a correct version of TeamViewer that matches the OS version.  TeamViewer provides a way for me to operate my computer system downstairs and eliminates the need for me to use the stairs significantly.

Obviously, TeamViewer is a recognized software brand and should be considered safe to use.