Some questions...

1. http://www.codeigniter.com/user_guide/ge...quirements (Virtually the very first entry in the docs)

2. http://forum.codeigniter.com/thread-6650...ile+upload There might be an issue, not read all the details myself but it seems to have been addressed. https://github.com/bcit-ci/CodeIgniter/issues/4887 (I found this searching the forum for you, 3rd entry in search results).

3. They don't work? Been a long time since I used them but can you give an example of one that does not? I believe a lot of effort goes into maintaining the docs but while CI4 is under such heavy development it is possible something has been overlooked or missed. It is always possible an error or typo slipped in. If you can identify any errors that would help the CI team to maintain the docs.