Did the famous Wilhelm Scream, used in all the previous Star Wars films, appear in The Last Jedi?
I was able to attend a screening of the movie today at Skywalker ranch. After the movie I spoke with the sound designer (Ren Klyce) and the sound supervisor (Matthew Wood) and asked them specifically about this as I swore that Kylo's lightsaber was an altered Wilhelm. They said they did not use the Wilhelm in The Last Jedi or Rogue One. They hinted that they have been using a new sound in a similar fashion for the last few movies they worked on but didn't want to point it out just yet. I thought it was a nice little teaser for the future.
Matthew Woods who did the audio for the last jedi confirmed there was no Whilem Scream in Star Wars: The Last Jedi:
The film did not include a single instance of the famous Wilhelm Scream. Mathew Wood, the supervising sound editor on The Last Jedi, recently revealed that Skywalker Sound has decided to "move on." According to Wood...
"In this movie, we decided to move from the Wilhelm scream. We're letting the past die, as Kylo Ren says."
I was searching the internet because I could have sworn I heard the WIlhelm Scream in a swooping motion of Kylo Rens light-saber during one of the scenes. I haven't found anyone else say they noticed it, though I am all but certain it was there.
EDIT: It appears I was right. In front of the mine doors immediately after Luke ducks Kylo Rens first attack.