When was the last The Simpsons episode made?

As of my limited knowledge up to March 2023, the final episode of The Simpsons that had aired so far was the The Winter Of Our Monetized Content, which was the 21st episode of the show's 34th season. It was aired on May 22, 2022 in USA.

However, it is important to note that this information might be outdated, as new episodes may have aired after March 2023. To confirm this information and obtain the most up-to-date accurate answer, I recommend checking the official website or social media pages of The Simpsons, or a reliable source for television show information.