# Brown Bicycle Bears (v0.2.7)¶

There are some important changes for this version that may break some Carousel models.

## Parameter Files¶

Carousel now recommends using class attributes instead of JSON parameter files to declare outputs, data, formulas, calculations, simulations and models. Parameter files can still be used and there are currently no plans to deprecate them.

## Simulation Filename¶

The use of a simulation filename and path has been deprecated. If you use a simulation filename and path in your model and you have enabled logging you should see a exceptions.DeprecationWarning. The preferred style is to set simulation parameters in your simulation class as class attributes.

Also the interval_length simulation attribute has been renamed to interval and simulation_length has been renamed to sim_length, which are the names that are used internally.

For more information on these changes and the simulation layer please see the Models and Simulations tutorial.

## Model Subclass¶

The BaseModel subclass has been removed. Please use Model instead.