Can quick-support provide access to a MAC running an older version

Volunteer_50

I'm trying to help a friend in a nursing home with her MAC. We have succeeded in installing Teamviewer on her computer however I cannot connect because the version on her computer is too old. We attempted to update her version but it didn't work maybe because her OS is too old. We also tried Quick-Support with same result. Do we have to uninstall the older version of Teamviewer before Quick-Support works or is Quick-Support also limited to newer versions? Please help we have used many hours on this all ready.