New Proxy Core (mhils, [blog post](https://www.mitmproxy.org/posts/releases/mitmproxy7/))
Mitmproxy has a completely new proxy core, fixing many longstanding issues:
* **Secure Web Proxy:** Mitmproxy now supports TLS-over-TLS to already encrypt the connection to the proxy.
* **Server-Side Greetings:** Mitmproxy now supports proxying raw TCP connections, including ones that start
with a server-side greeting (e.g. SMTP).
* **HTTP/1 – HTTP/2 Interoperability:** mitmproxy can now accept an HTTP/2 connection from the client,
and forward it to an HTTP/1 server.
* **HTTP/2 Redirects:** The request destination can now be changed on HTTP/2 flows.
* **Connection Strategy:** Users can now specify if they want mitmproxy to eagerly connect upstream
or wait as long as possible. Eager connections are required to detect protocols with server-side
greetings, lazy connections enable the replay of responses without connecting to an upstream server.
* **Timeout Handling:** Mitmproxy will now clean up idle connections and also abort requests if the client disconnects
in the meantime.
* **Host Header-based Proxying:** If the request destination is unknown, mitmproxy now falls back to proxying
based on the Host header. This means that requests can often be redirected to mitmproxy using
DNS spoofing only.
* **Internals:** All protocol logic is now separated from I/O (["sans-io"](https://sans-io.readthedocs.io/)).
This greatly improves testing capabilities, prevents a wide array of race conditions, and increases
proper isolation between layers.
Additional Changes
* mitmproxy's command line interface now supports Windows (mhils)
* The `clientconnect`, `clientdisconnect`, `serverconnect`, `serverdisconnect`, and `log`
events have been replaced with new events, see addon documentation for details (mhils)
* Contentviews now implement `render_priority` instead of `should_render`, allowing more specialization (mhils)
* Addition of block_list option to block requests with a set status code (ericbeland)
* Make mitmweb columns configurable and customizable (gorogoroumaru)
* Automatic JSON view mode when `+json` suffix in content type (kam800)
* Use pyca/cryptography to generate certificates, not pyOpenSSL (mhils)
* Remove the legacy protocol stack (Kriechi)
* Remove all deprecated pathod and pathoc tools and modules (Kriechi)
* In reverse proxy mode, mitmproxy now does not assume TLS if no scheme
is given but a custom port is provided (mhils)
* Remove the following options: `http2_priority`, `relax_http_form_validation`, `upstream_bind_address`,
`spoof_source_address`, and `stream_websockets`. If you depended on one of them please let us know.
mitmproxy never phones home, which means we don't know how prominently these options were used. (mhils)
* Fix IDNA host 'Bad HTTP request line' error (grahamrobbins)
* Pressing `?` now exits console help view (abitrolly)
* `--modify-headers` now works correctly when modifying a header that is also part of the filter expression (Prinzhorn)
* Fix SNI-related reproducibility issues when exporting to curl/httpie commands. (dkasak)
* Add option `export_preserve_original_ip` to force exported command to connect to IP from original request.
Only supports curl at the moment. (dkasak)
* Major proxy protocol testing (r00t-)
* Switch Docker image release to be based on Debian (PeterDaveHello)
* Multiple Browsers: The `browser.start` command may be executed more than once to start additional
browser sessions. (rbdixon)
* Improve readability of SHA256 fingerprint. (wrekone)
* Metadata and Replay Flow Filters: Flows may be filtered based on metadata and replay status. (rbdixon)
* Flow control: don't read connection data faster than it can be forwarded. (hazcod)
* Docker images for ARM64 architecture (hazcod, mhils)
* Fix parsing of certificate issuer/subject with escaped special characters (Prinzhorn)
* Customize markers with emoji, and filters: The `flow.mark` command may be used to mark a flow with either the default
"red ball" marker, a single character, or an emoji like `:grapes:`. Use the `~marker` filter to filter on marker
characters. (rbdixon)
* New `flow.comment` command to add a comment to the flow. Add `~comment <regex>` filter syntax to search flow comments.
(rbdixon)
* Fix multipart forms losing `boundary` values on edit. (roytu)
* `Transfer-Encoding: chunked` HTTP message bodies are now retained if they are below the stream_large_bodies limit.
(mhils)
* `json()` method for HTTP Request and Response instances will return decoded JSON body. (rbdixon)
* Support for HTTP/2 Push Promises has been dropped. (mhils)
* Make it possible to set sequence options from the command line. (Yopi)