Automatically generate( and apply) a valid password for a new user


there's a new feature in Wordpress 4.3 that stopped sending the password to the new user by email. This is causing me a lot of pain since I really want to automatically send a nice email to my customers with every information they need.

I know it might be a little insecure but whatever.

How should I proceed to either disable the new feature or generate a valid working password to my user.