I need to verify the actual release dates. Let me check: Transformers: Age of Extinction was released in 2014, The Last Knight in 2017. Web DLs are typically available around the same time as the theater release, but sometimes a bit delayed. If the user is referring to a 2021 Web DL, maybe it's pirated or an illegal download site, which I should caution against. Alternatively, maybe a streaming service added it in 2021, but I'm not aware of that. Alternatively, maybe the user is confused about the dates.

Wait, "Transformers: Age of Extinction" is the fourth movie in the live-action Transformers series, released in 2014. But the title here mentions 2017 and Web DL 2021. Maybe there's a confusion here. Let me check the release dates. The fourth movie, Age of Extinction, came out in June 2014. There was a Blu-ray release later that year. Web DL usually refers to a digital copy released in a compressed format, often in the same year as the movie. So a Web DL in 2021 for a 2014 movie seems off. Maybe the user is looking for a version that was released in 2021, but that doesn't align with the movie's timeline. Alternatively, maybe there's a mistake in the title. Perhaps they meant "Transformers: The Last Knight," which is the fifth movie, released in 2017. That could be a mix-up. Let me verify the titles and release dates to avoid confusion.

In any case, the blog post should address the movie itself, its context, the Web DL format for that time, and its significance. Also, include a note about legal sources for viewing. Need to ensure accuracy, correct the title if necessary, and avoid promoting piracy. Also, highlight the director, cast, reception, and place in the franchise. Maybe touch on the decline of the series' box office in later films.

The user might be seeking an analysis or discussion about the 2017 movie, perhaps in the context of a 2021 digital copy. They might also be interested in the technical aspects like the Web DL version's quality, how it compares to other releases, or maybe a review. Another angle is how the film fits into the Transformers series as a whole, especially considering the series was winding down with Michael Bay's direction. Also, considering the 2021 release of a Web DL copy, maybe there's interest in how long it took for different versions to be released or the significance of that delay.

I should structure the blog post with an introduction explaining the movie and the context of the Web DL release. Then discuss the movie's plot, direction, and box office success. Next, delve into the technical aspects of the Web DL format—bitrate, resolution, availability, perhaps where to find it. Then, a section analyzing the legacy of the movie and the series as a whole, leading up to the final movie. Also, address why someone would prefer a Web DL over a Blu-ray or other formats. Potential challenges include clarifying any confusion between Age of Extinction and The Last Knight. Need to make sure the title is correct. Maybe mention both if there's a mix-up. Also, check if there's any official 2021 release for The Last Knight, but I think it would have launched its Web DL closer to 2018. The user might have incorrect info.