With the release of macOS Catalina 10.15, Apple requires applications to go through an involved notarization process. The 2020R1 version of BlackLight has not been notarized by Apple yet, therefore, when installing this version of BlackLight a warning appears:
"BlackLight_Mac_Setup_2020R1.pkg" can't be opened because Apple cannot check it for malicious software.
To bypass this warning and complete the 2020R1 installation, please follow the steps below.
1- Right-click on BlackLight_Mac_Setup_2020R1.pkg and choose Open With -> Installer (default)
2- Click the 'Open' button when the warning appears
3- A Verifying message will display for a few seconds as the BlackLight Installer opens
4- After verifying, the BlackLight 2020R1 installer will appear to guide you through installation
5- At the end of the 2020R1 installation, a macOS message will prompt to allow access to the location of the BlackLight installer
If allowed access, a final macOS message will prompt to discard the BlackLight Installer to the trash to save space on your Mac.
Success! You are now ready to use BlackLight 2020R1 on macOS Catalina.
If you need further assistance, contact firstname.lastname@example.org