Can I still use old Korean won?

Good day, I have a question regarding the usability of old Korean won currency. With the rapid advancements in technology and the economy, I'm wondering if the old Korean won notes and coins are still considered legal tender and can be used for transactions in stores, restaurants, or any other business establishments. Could you please clarify if these old currency notes and coins are still accepted, or have they been phased out and replaced by newer versions? I'd appreciate any information you could provide on this matter. Thank you in advance.