The Japanese electronic tax filing system's browser support policy is to support browsers that come preinstalled with the OS, period, actual marketshare be damn

The Japanese electronic tax filing system's browser support policy is to support browsers that come preinstalled with the OS, period, actual marketshare be damned. This makes them support IE, Edge and Safari, but not Chrome nor Firefox. (While some newer parts of the system do support them, most of the critical parts still do not. Additionally, since the system still only supports the EdgeHTML Edge, the Chromium Edge automatic rollout is delayed to April specifically for Japan, to avoid confusion during the February-March tax filing season.) The only way to make them stop supporting IE is to have the OS itself stop bundling it - which, like it was mentioned elsewhere in this discussion, is probably never going to happen.