# mitmproxy v12.0.0 — mitmproxy 12.0.0 - Product: mitmproxy (https://whatsnew.fyi/product/mitmproxy) - Vendor: mitmproxy - Date: 2025-04-29 - Version: v12.0.0 - Original notes: https://github.com/mitmproxy/mitmproxy/releases/tag/v12.0.0 - Permalink: https://whatsnew.fyi/product/mitmproxy/releases/v12.0.0 - Labels: Platforms: Desktop What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog. Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'. --- - **changed** — Contentviews can now be interactive and re-encode prettified data, with syntax highlighting signaled off-band based on tree-sitter - **changed** — Contentview API has been drastically simplified, with contentviews now returning a plain string with prettified data - **added** — Contentviews can now be written in Rust for better performance and access to the crates ecosystem - **changed** — Replace existing gRPC and Protobuf contentviews with an interactive contentview that supports both existing proto definitions and unknown protos - **changed** — MsgPack contentview is now interactive - **added** — Add a new feature to store streamed bodies for requests and responses - **added** — Add support for TLS 1.3 Post Handshake Authentication - **added** — Add CRL entries to dummy cert when the upstream certificate has some - **fixed** — Fix a bug where mitmproxy would incorrectly send empty HTTP/2 data frames - **fixed** — Fix a bug where mitmdump would exit prematurely in server replay mode - **fixed** — Fix a bug where WebSocket Messages view jumps to top when a message is received - **added** — Create content view for Socket.IO over WebSocket transport - **fixed** — Correctly forward HTTP_1_1_REQUIRED errors in HTTP/2 streams - **fixed** — Fix a bug where HAR export would crash for malformed flows - **fixed** — Fix a bug where mitmweb would crash when viewing flows with undefined headers - **fixed** — Fix a bug where mitmproxy does not listen on IPv4 and IPv6 by default in wireguard mode - **changed** — Adjust popover placement for browsers that support anchor positioning - **fixed** — Fix mitmweb crash when searching or highlighting using ~h, ~hq, or ~hs - **changed** — mitmproxy.dns.Message has been renamed to mitmproxy.dns.DNSMessage - **added** — Add support for selecting multiple flows in mitmweb using Ctrl+Click and Shift+Click with support for deleting, duplicating, marking, reverting, replaying, resuming, and aborting flows ###### New Contentview System ([#7623](https://github.com/mitmproxy/mitmproxy/pull/7623), @mhils) - Contentviews can now be interactive and re-encode prettified data. For example, the new Protobuf view pretty-prints to YAML, which the user can edit and then re-serialize into binary representation. - Replace the existing gRPC and Protobuf contentviews with an interactive contentview that supports both existing proto definitions and completely unknown protos. - The MsgPack contentview is now interactive, too. - The contentview API has been drastically simplified. Contentviews now return a plain `str` with the prettified data. Syntax highlighting is now signaled off-band (and based on [tree-sitter]). - Docs: Add new documentation page and API reference for contentviews. - Contentviews can now be written in Rust for better performance and access to the crates ecosystem. ###### Other Changes - Add a new feature to store streamed bodies for requests and responses. ([#7637](https://github.com/mitmproxy/mitmproxy/pull/7637), @mkiami) - Add support for TLS 1.3 Post Handshake Authentication. ([#7576](https://github.com/mitmproxy/mitmproxy/pull/7576), @mhils, @cataggar) - Add search functionality to the documentation. ([#7603](https://github.com/mitmproxy/mitmproxy/pull/7603), @mhils) - Introduce a new theme for docs.mitmproxy.org. ([#7593](https://github.com/mitmproxy/mitmproxy/pull/7593), @mhils) - Add CRL entries to dummy cert when the upstream certificate has some. ([#7609](https://github.com/mitmproxy/mitmproxy/pull/7609), @Yepoleb, @JordanPlayz158) - Fix a bug where mitmproxy would incorrectly send empty HTTP/2 data frames. ([#7574](https://github.com/mitmproxy/mitmproxy/pull/7574), @mhils, @Dieken) - Enhance homebrew installation command for Brewfile users. ([#7566](https://github.com/mitmproxy/mitmproxy/pull/7566), @AntoineJT) - Fix a bug where mitmdump would exit prematurely in server replay mode. ([#7571](https://github.com/mitmproxy/mitmproxy/pull/7571), @mhils) - Fix a bug where WebSocket Messages view jumps to top when a message is received ([#7572](https://github.com/mitmproxy/mitmproxy/pull/7572), @DenizenB) - Create content view for Socket.IO over WebSocket transport ([#7570](https://github.com/mitmproxy/mitmproxy/pull/7570), @DenizenB) - Correctly forward HTTP_1_1_REQUIRED errors in HTTP/2 streams. ([#7575](https://github.com/mitmproxy/mitmproxy/pull/7575), @mhils) - Fix a bug where HAR export would crash for malformed flows. ([#7666](https://github.com/mitmproxy/mitmproxy/pull/7666), @mhils) - Fix a bug where mitmweb would crash when viewing flows with undefined headers. ([#7595](https://github.com/mitmproxy/mitmproxy/pull/7595), @emanuele-em) - Fix a bug where mitmproxy does not listen on IPv4 and IPv6 by default in wireguard mode. ([#7589](https://github.com/mitmproxy/mitmproxy/pull/7589), @errorxyz) - Adjust popover placement for browsers that support anchor positioning (Chrome, Edge) ([#7642](https://github.com/mitmproxy/mitmproxy/pull/7642), @lups2000) - Fix mitmweb crash when searching or highlighting using ~h, ~hq, or ~hs. ([#7652](https://github.com/mitmproxy/mitmproxy/pull/7652), @lups2000) - `mitmproxy.dns.Message` has been renamed to `mitmproxy.dns.DNSMessage` ([#7670](https://github.com/mitmproxy/mitmproxy/pull/7670), @mhils) - Added support for selecting multiple flows in mitmweb using Ctrl+Click and Shift+Click. Multi-selection is now supported for deleting, duplicating, marking, reverting, replaying ,resuming, and aborting flows. ([#7319](https://github.com/mitmproxy/mitmproxy/pull/7319), @lups2000, @mhils) [tree-sitter]: https://tree-sitter.github.io/tree-sitter/