Twitter has strengthened it’s security and also has made Password Resets more streamlined.
You can now choose between your phone number and your email associated with your Twitter account as options for resetting your account. This could come in useful if you don’t have access to either the phone number or the email account that is currently associated with your Twitter account.
The other change strengthens the security of your Twitter account. Using factors such as location, device being used and login history, Twitter is able to determine whether it is really you accessing your Twitter account or not. If Twitter suspects that someone else is trying to get into your account, then Twitter will ask a security question (Which is decided by you; Don’t make the answer easy to guess) . Additionally, an email will be sent to you notifying you of suspicious activity on your account. This may be able to prevent hackers from hijacking your account.
The new security update comes a year after Twitter introduced and implemented Two-Factor authentication which had further strengthened the login process.
Sources: Twitter Blog