PBKDF2 is not deprecated, but it is no longer the recommended default for new systems. Here is the honest, practical answer for developers: when PBKDF2 is still acceptable, when you should reach for Argon2id instead, and how to decide for your system.
Most "use bcrypt" posts are from 2014. Argon2 won the Password Hashing Competition in 2015 and nobody updated. Here is the actual 2026 decision framework for picking a password hashing algorithm.