.. _aiohttp_whats_new_3_0: ========================= What's new in aiohttp 3.0 ========================= async/await everywhere ====================== The main change is dropping ``yield from`` support and using ``async``/``await`` everywhere. Farewell, Python 3.4. The minimal supported Python version is **3.5.3** now. Why not *3.5.0*? Because *3.5.3* has a crucial change: :func:`asyncio.get_event_loop()` returns the running loop instead of *default*, which may be different, e.g.:: loop = asyncio.new_event_loop() loop.run_until_complete(f()) Note, :func:`asyncio.set_event_loop` was not called and default loop is not equal to actually executed one. Application Runners =================== People constantly asked about ability to run aiohttp servers together with other asyncio code, but :func:`aiohttp.web.run_app` is blocking synchronous call. aiohttp had support for starting the application without ``run_app`` but the API was very low-level and cumbersome. Now application runners solve the task in a few lines of code, see :ref:`aiohttp-web-app-runners` for details. Client Tracing ============== Other long awaited feature is tracing client request life cycle to figure out when and why client request spends a time waiting for connection establishment, getting server response headers etc. Now it is possible by registering special signal handlers on every request processing stage. :ref:`aiohttp-client-tracing` provides more info about the feature. HTTPS support ============= Unfortunately asyncio has a bug with checking SSL certificates for non-ASCII site DNS names, e.g. `https://историк.рф `_ or `https://雜草工作室.香港 `_. The bug has been fixed in upcoming Python 3.7 only (the change requires breaking backward compatibility in :mod:`ssl` API). aiohttp installs a fix for older Python versions (3.5 and 3.6). Dropped obsolete API ==================== A switch to new major version is a great chance for dropping already deprecated features. The release dropped a lot, see :ref:`aiohttp_changes` for details. All removals was already marked as deprecated or related to very low level implementation details. If user code did not raise :exc:`DeprecationWarning` it is compatible with aiohttp 3.0 most likely. Summary ======= Enjoy aiohttp 3.0 release! The full change log is here: :ref:`aiohttp_changes`.