Error "The 'targetFramework' attribute in the..." after HRPro Upgrade

The error "The 'targetFramework' attribute in the <compilation> element of the Web.config file is used only to target version 4.0 and later of the .NET Framework" appear when accessing Employee Portal or Web Client after HRPro Upgrade.

Solutions: 

Web Client 18.10 and Employee Portal 18.10 or above required .Net Framework 4.7.2 or above. Please download and install .Net Framework 4.7.2 Runtime at 

Download .NET Framework 4.7.2 | Free official downloads (microsoft.com) 🡕 

or 

Download .NET Framework | Free official downloads (microsoft.com) 🡕