TeamViewer publishes regular security updates. A version from 2016–2018 lacks fixes for known CVEs (Common Vulnerabilities and Exposures). For example, older TeamViewer versions were susceptible to:
Users often target this specific version because TeamViewer requires both the local and remote devices to have compatible versions. If one device is "stuck" on an older version of TeamViewer 12, the other must match it to avoid connection failures. teamviewer 120259 download free
After installation, you can use TeamViewer to: TeamViewer publishes regular security updates