No, Dog Man 11 is not the last book. Dog Man 11 is the latest book in the series, which was released in 2020. Creators Dav Pilkey and Scholastic have already announced plans for future books in the series.
According to an article on Scholastic's website, "Dog Man 12 is coming soon—and it's going to be EPIC!" The article continues: "Keep your eyes peeled for the 12th adventure of the beloved canine hero, which will arrive most likely sometime in 2021."
Despite being the latest book so far, Dog Man 11 is far from the last in the series. You can look forward to many more books in the future. To find out more about them, be sure to keep an eye on Scholastic's website or social media accounts. They'll have all the latest news and updates about Dog Man 12 and beyond.
