Flip Phone Support for App

We have an employee that is visually impaired that works standing up and can not access a desk phone. He had been using an older smartphone, that just forwards the number over wifi, but since you retired that version of the app, we can not find a smartphone that will work for him. Having an option for the application to be used on a flip device would certainly be more inclusive than having no options at this time. Thank you for looking into this.