I use the example code:
$user = BackendAuth::register([
'name' => 'Some User',
'login' => 'someuser',
'email' => '[email protected]',
'password' => 'changeme',
'password_confirmation' => 'changeme'
]);
Location: https://octobercms.com/docs/backend/users#backend-auth-facade
I got the following error:

It's first_name & last_name not name, was recently updated in the docs on github: https://github.com/octobercms/docs/blob/master/backend-users.md#backend-user-helper
I changed the code, but the error message is same.
October version: 1.0.469
I use it in the beforeSave() method of my plugin. If I put it in the boot() method of Plugin.php I get the following error:

@gergo85 try using v1.1.0 via composer instead.
@gergo85 try using v1.1.0 via composer instead.
Updating via composer is throwing incompatible error
[InvalidArgumentException]
Package october/october at version 1.1.0 has a PHP requirement incompatible with your PHP version (7.0)
PHP Version 7.4.6
How to update the website to v1.1.0 from v1.0.469?
@bhargavy @gergo85 you'll need to copy the updated composer.json file from here and apply that to your project - making sure to bring across any additional requirements you may have for your project (within require or require-dev). You should then be able to run composer update and get the necessary updates.
@bhargavy sounds like your composer install or PHP CLI is running an older version of PHP than your web server.
I did it and I got the following error message:
Warning: require(C:\xampp\htdocs\vendor\composer/../october/rain/src/Parse/Assetic/Less/lessc.inc.php): failed to open stream: No such file or directory in C:\xampp\htdocs\vendor\composer\autoload_real.php on line 66
Fatal error: require(): Failed opening required 'C:\xampp\htdocs\vendor\composer/../october/rain/src/Parse/Assetic/Less/lessc.inc.php' (include_path='C:\xampp\php\PEAR') in C:\xampp\htdocs\vendor\composer\autoload_real.php on line 66
delete vendor, modules, & composer.lock, then run composer install using the proper version of PHP and the updated composer.json.
I deleted the folders and run the run composer install. The vendor/autoload.php file not generated.

if you're not using the tests folder then remove the require-dev dependencies and the references to the test cases from your composer file.
It works! Thank you very much!
How to update the database?
Unfortunately the issues are still there :(
@bennothommo are you able to take a look at the original issue report with the register method failing?
@LukeTowers found the issue - it's that "guarded" attributes change that Laravel added recently. The password_confirmation field is being dropped from the data before validation because it doesn't correlate to a column in the users table, which causes validation to fail. We had to convert the File model to use fillable attributes as opposed to guarded, but I'm not sure if we can do the same here because there's more likelihood that people are overwriting or extending the User model.
@bennothommo would that affect them though if they weren't overriding the guarded / fillable attributes?
Is there any quick solution to solve this issue? I need it for an active project.
@bennothommo shouldnt be password_confirmation defined with purgeable? https://octobercms.com/docs/database/traits#purgeable
@bennothommo I haven't heard anything from @taylorotwell or @driesvints on our request for the original security report, so I'd say revert their final fix and replace it with the arrow fix instead.
@LukeTowers just emailed you the original report.
@gergo85 @bennothommo can you guys test https://github.com/octobercms/library/pull/533 and let me know if that resolves the issue?
I replaced the vendor/october/rain foldet to new version, but the issues are still there.
I replaced the vendor/october/rain foldet to new version, but the issues are still there.
What did you do exactly?
I deleted the files of vendor/october/rain folder and I copied the new version (github.com/octobercms/library) to this folder.
You should check the files changed in https://github.com/octobercms/library/pull/533 manually and verify that they contain the changes from that PR.
I use the fix/5313 branche, but the issue is same.
It seems to be working for @RomainMazB
Most helpful comment
@LukeTowers just emailed you the original report.