<!-- See https://github.com/Microsoft/calculator/blob/main/docs/NewFeatureProcess.md for suggestions on how to write a good feature pitch. Just want to submit an idea quickly? Try Feedback Hub instead: https://insider.windows.com/en-us/fb/?contextid=130 --> **Problem Statement** <!-- What problem are we trying to solve? Who’s the target audience? Is there a customer need or pain point we need to remedy? Is there a business goal or metric we are trying to improve? Do we have a hypothesis we want to prove or disprove? --> I didn't update, it updated somehow, and I get used to the old interface, and now find nowhere to back to the old interface. **Proposal** <!-- How will the solution/feature help us solve the problem? How will it meet the target audience’s needs? If there are business goals or metrics, how does this improve them? --> give a switch so we can switch back to the old interface or back to the new.