Does any software that requires an invitation code require a mobile phone number?

Yes.

1. Mobile phone numbers can be used to verify the user's identity to ensure that the user is a real person. This is especially important for some software that requires invitation codes, because these software often need to limit the number of new users in order to maintain the quality of their communities.

2. Mobile phone numbers can be used to send verification codes, thereby improving the security of user accounts. By requiring users to provide their mobile phone number, the software can send a verification code to the user's phone to ensure that only the real user can access their account.

3. Some software will use users’ mobile phone numbers for marketing activities, such as sending promotional text messages or phone calls. Although this may bother some users, mobile phone numbers are still necessary information for some software.