What is the oldest motherboard still used in most systems?

The oldest motherboards still in use in many systems are typically those supporting the LGA 1151 socket, which was introduced in 2015 for Intel's 6th generation Core processors. While newer technologies have emerged, many users continue to utilize these motherboards due to their compatibility with a range of CPUs and the availability of budget-friendly components. However, as technology advances, even these older motherboards are gradually being phased out in favor of more recent standards.