$_FILES['userfile']['type'] Mime type different than the $this->upload->data() mine type?

[eluser]CroNiX[/eluser]
You can try to update your mimes.php file with the one from CI3 on github. https://github.com/EllisLab/CodeIgniter/.../mimes.php

It has a different definition for pdf than 2.2:
'pdf' => array('application/pdf', 'application/force-download', 'application/x-download', 'binary/octet-stream'),

As far as why it gets binary/octet-stream, it could be whatever program/library is creating the pdf. also some browsers have had issues setting the correct mime type.

You could try to upload from a different browser to see if it changes, and also try using PDFs from a variety of different sources.