In most translations, after John 7:52, we read this:
[THE EARLIEST MANUSCRIPTS DO NOT INCLUDE 7:53-8:11]
In his commentary on John, D.A. Carson comments:
These verses are present in most of the medieval Greek miniscule manuscripts, but they are absent from virtually all early Greek manuscripts that have come down to us, representing great diversity of textual traditions . . . All the early church Fathers omit this narrative: in commenting on John, they pass immediately from 7:52 to 8:12 . . . Even if someone should decide that the material is authentic, it would be very difficult to justify the view that the material is authentically [from John]: there are numerous expressions and constructions that are found nowhere in John, but are characteristic of [Matthew, Mark and Luke], Luke in particular.
On the other hand, there is little reason for doubting that the event here described occurred, even if in its written form it did not in the beginning belong to the canonical books.