Will an overhead legacy 850 garage door opener open with a lift master keypad?

Yes, a LiftMaster keypad can operate an overhead legacy 850 garage door opener if the opener is compatible with the keypad's frequency and technology. Most LiftMaster keypads are designed to work with various LiftMaster models, but you should check the specific compatibility with your legacy model. If the legacy 850 uses a rolling code or fixed code system that matches the keypad, it should function properly. Always refer to the user manuals for both devices to ensure compatibility and proper programming.