Software like that needs to consist of two parts, the frontend client and backend server. Even if the software is a hosted web app, the frontend needs to exist

Software like that needs to consist of two parts, the frontend client and backend server. Even if the software is a hosted web app, the frontend needs to exist as a separate part. This way, the server backend can be upgraded over time to include better security, better efficiency, etc while leaving the client be so that the UI can remain frozen in whatever version the company initially trained their employees on.