# Backward Compatibility

`argon2_cffi` has a very strong backward compatibility policy. Generally speaking, you shouldn’t ever be afraid of updating.

If breaking changes are needed do be done, they are:

1. …announced in the changelog.
2. …the old behavior raises a `DeprecationWarning` for a year.
3. …are done with another announcement in the changelog.

What explicitly may change over time are the default hashing parameters and the behavior of the CLI.