# 2.0.0 Release Notes

Channels 2.0 is a major rewrite of Channels, introducing a large amount of changes to the fundamental design and architecture of Channels. Notably:

- Data is no longer transported over a channel layer between protocol server and application; instead, applications run inside their protocol servers (like with WSGI).
- To achieve this, the entire core of channels is now built around Python’s `asyncio` framework and runs async-native down until it hits either a Django view or a synchronous consumer.
- Python 2.7 and 3.4 are no longer supported.

More detailed information on the changes and tips on how to port your applications can be found in our What’s new in Channels 2? documentation.

## Backwards Incompatible Changes

Channels 2 is regrettably not backwards-compatible at all with Channels 1 applications due to the large amount of re-architecting done to the code and the switch from synchronous to asynchronous runtimes.

A migration guide is available, and a lot of the basic concepts are the same, but the basic class structure and imports have changed.

Our apologies for having to make a breaking change like this, but it was the only way to fix some of the fundamental design issues in Channels 1. Channels 1 will continue to receive security and data-loss fixes for the foreseeable future, but no new features will be added.