Can the 'auto' algorithm of the Symfony Security encoder change encoding method?

In Symfony 4.3, it is recommended to use the auto option for encoding algorithm:

# config/packages/security.yamlsecurity:# ...encoders:    # use your user class name here    App\Entity\User:        # Use native password encoder        # This value auto-selects the best possible hashing algorithm.        algorithm: auto

My question is in regards to the comment in the code above: can the algorithm change if the "best possible" algorithm changes? If so, how will this affect the currently existing stored passwords?