Your change is a significant improvement, but the language still seems a bit off. Specifically, “and all those” and “and all that” stand out. Try one of these, but note that I did not have full context of the sentence:
"There are still requests, responses, headers, and other typical elements from HTTP."
"Requests, responses, headers, and other typical elements still exist from the HTTP specification."
"Requests, responses, headers, and other typical elements remain from HTTP."
Should it also reference HTTP/1.x directly rather than just the generic HTTP?
Is “typical” actually important? In my examples above, that word can probably be removed for the better.
Also the plurality of the sentence should match; note how I changed request to requests above.
With lists, the comma placement after the and seems to vary significantly with region. Here, we typically terminate the term immediately before “and” with a comma, but not all areas do so. Either is correct, as long as it’s consistent.