macOS 10.15 (Catalina): “EPSON Printer.pkg can’t be opened” when trying to install a driver

Relates to:

All Epson drivers

Background:

When installing a driver or piece of software on macOS Catalina (10.15) the user may see an error message which prevents the installation completing.

Explanation:

This error presents when installing a piece of software which has not been notarized (digitally signed) by Apple, which is a requirement for macOS 10.15.

To fix this issue click on the OK button shown on the message window. Then press and hold the command key, click on the install icon and select Open. The install should then proceed as normal.