So the maintainers of the file are the WordPress team – this is a core WordPress file. : )
That being said, the code is not the problem here, per say. I’m not sure how the old file worked around the issue, but the problem is that you’re trying to send an email without a “from” address – and you can’t send emails without a “from” email address.
From the logs you posted, the culprit seems to be the theme file “enigma-parallax/header.php” — on line 99, it seems like there might have been a spot to set a “From” email address, and that was not done, or not done properly? (you rlogs show “‘From: <>\r\nRepl…'”)
If you can;t isolate the issue in there, please post the code of the “enigma-parallax/header.php” file so we can better help you out.
Thanks!