Upgrade to 4.0 gives fatal error on login

hash() is a PHP-function introduced with PHP 5.1.2.
Do you know which php-version you are running?

5.3.10, according to phpinfo()

Accoring to https://php.net/manual/en/book.hash.php, Hash in enabled by default, but can be deactivated with parameter –disable-hash

Check you phpinfo(), if enabled there is a block with title “hash” and infos about hash support and hashing engines.

If not, check the very first block of phpinfo() around line 5 ist “configure command”. if you find “–disable-hash” there, you’ll have to recompile your PHP or ask your hoster to enable hashing-support in PHP.

Quite a bit down on the page in the “session” section I find these two for the search on “hash”. There is no other mention of it anywhere else.

session.hash_bits_per_character 4 4
session.hash_function 0 0

If it is handy, I can put the url to the page with the phpinfo() command here? Dont know wether thats wise security wise…

Thanks for helping me!

Don’t post phpinfo() public.
To much info for ‘bad guys’.

session.hash* is part of the Session-Block.

For me, it does not look like your host supports hash()-functions. I’d recommend contacting your hoster and ask for hash()-support or go back and restore an older version of WordPress.

Sorry!

Ok I will conatct him, he’s a friend hopefully we can work it out ??

How would I revert back to the previous version without being able to login in case we cant get hash() to work?

Do not get my wrong, but if you backup-process requires a working instance of your install to restore the data, it’s broken be design.
Crossing fingers you have Database-Dump and old files somewhere on your host where you can access them via FTP.

You should read https://codex.www.ads-software.com/WordPress_Backups and overthink your process.
I do a mysql-dump of my database via phpmyadmin and gzip all files of my domain regulary and manually before I update wordpress.
Having a wordpress plugin for this may not be the best idea unless it puts there files somewhere where you can access them.

Good luck!

Unfortunally this also means I can not login to restore a backup.

There are other ways of breaking into your website.
Login to your website hosting management, you will be able to restore files and databases. You can also use FTP to access files. The web hosting and FTP logins are independent of your WordPress login.

RossMitchel, simply remove the 4.0 dirs & files, and upload the extracted backup? Dont know if that gives errors with permissions etc. I’m a bit rusty to do it on the server in a shell…

Be careful not to remove your plugins and uploads and do not forget the database. WordPress 3.x files may not work with WordPress 4.0 database.

After I put the files back, can I restore the database on the admin panel?

Gosh everything works, even putting in a wrong password gives me an error that the pass is wrong.

If this is the path, I wonder how things will go in the future in regards to security. I mean, if I can never update anymore…

You need to connect the extension hash in php

Вам необходимо подключить расширение hash в php

Hello am wondering if you can help.. I have just done a manual installation of WordPress 4.0 and followed the instructions carefully. Now when I try to go on the site I get a blank white screen…

Can you help please??