Hello,

We just released our first 0.4.8.x series alpha.

Announcement: https://forum.torproject.net/t/alpha-release-0-4-8-1-alpha/7816

The ChangeLog is below:

Changes in version 0.4.8.1-alpha - 2023-06-01 This is the first alpha of the 0.4.8.x series. Two major features in this version which are Conflux and onion service Proof-of-Work (PoW). There are also many small features in particular, worth noting, the MetricsPort is now exporting more relay and onion service metrics. Finally, there are also numerous minor bugfixes included in this version.

o Major features (onion service, proof-of-work): - Implement proposal 327 (Proof-Of-Work). This is aimed at thwarting introduction flooding DoS attacks by introducing a dynamic Proof-Of-Work protocol that occurs over introduction circuits. This introduces several torrc options prefixed with "HiddenServicePoW" in order to control this feature. By default, this is disabled. Closes ticket 40634.

o Major features (conflux): - Implement Proposal 329 (conflux traffic splitting). Conflux splits traffic across two circuits to Exits that support the protocol. These circuits are pre-built only, which means that if the pre- built conflux pool runs out, regular circuits will then be used. When using conflux circuit pairs, clients choose the lower-latency circuit to send data to the Exit. When the Exit sends data to the client, it maximizes throughput, by fully utilizing both circuits in a multiplexed fashion. Alternatively, clients can request that the Exit optimize for latency when transmitting to them, by setting the torrc option 'ConfluxClientUX latency'. Onion services are not currently supported, but will be in arti. Many other future optimizations will also be possible using this protocol. Closes ticket 40593.

o Major features (dirauth): - Directory authorities and relays now interact properly with directory authorities if they change addresses. In the past, they would continue to upload votes, signatures, descriptors, etc to the hard-coded address in the configuration. Now, if the directory authority is listed in the consensus at a different address, they will direct queries to this new address. Implements ticket 40705.

o Minor feature (CI): - Update CI to use Debian Bullseye for runners.

o Minor feature (client, IPv6): - Make client able to pick IPv6 relays by default now meaning ClientUseIPv6 option now defaults to 1. Closes ticket 40785.

o Minor feature (compilation): - Fix returning something other than "Unknown N/A" as libc version if we build tor on an O.S. like DragonFlyBSD, FreeBSD, OpenBSD or NetBSD.

o Minor feature (cpuworker): - Always use the number of threads for our CPU worker pool to the number of core available but cap it to a minimum of 2 in case of a single core. Fixes bug 40713; bugfix on 0.3.5.1-alpha.

o Minor feature (lzma): - Fix compiler warnings for liblzma >= 5.3.1. Closes ticket 40741.

o Minor feature (MetricsPort, relay): - Expose time until online keys expires on the MetricsPort. Closes ticket 40546.

o Minor feature (MetricsPort, relay, onion service): - Add metrics for the relay side onion service interactions counting seen cells. Closes ticket 40797. Patch by "friendly73".

o Minor features (directory authorities): - Directory authorities now include their AuthDirMaxServersPerAddr config option in the consensus parameter section of their vote. Now external tools can better predict how they will behave. Implements ticket 40753.

o Minor features (directory authority): - Add a new consensus method in which the "published" times on router entries in a microdesc consensus are all set to a meaningless fixed date. Doing this will make the download size for compressed microdesc consensus diffs much smaller. Part of ticket 40130; implements proposal 275.

o Minor features (network documents): - Clients and relays no longer track the "published on" time declared for relays in any consensus documents. When reporting this time on the control port, they instead report a fixed date in the future. Part of ticket 40130.

o Minor features (fallbackdir): - Regenerate fallback directories generated on June 01, 2023.

o Minor features (geoip data): - Update the geoip files to match the IPFire Location Database, as retrieved on 2023/06/01.

o Minor features (hs, metrics): - Add tor_hs_rend_circ_build_time and tor_hs_intro_circ_build_time histograms to measure hidden service rend/intro circuit build time durations. Part of ticket 40757.

o Minor features (metrics): - Add a `reason` label to the HS error metrics. Closes ticket 40758. - Add service side metrics for REND and introduction request failures. Closes ticket 40755. - Add support for histograms. Part of ticket 40757.

o Minor features (pluggable transports): - Automatically restart managed Pluggable Transport processes when their process terminate. Resolves ticket 33669.

o Minor features (portability, compilation): - Use OpenSSL 1.1 APIs for LibreSSL, fixing LibreSSL 3.5 compatibility. Fixes issue 40630; patch by Alex Xu (Hello71).

o Minor features (relay): - Do not warn about configuration options that may expose a non- anonymous onion service. Closes ticket 40691.

o Minor features (relays): - Trigger OOS when bind fails with EADDRINUSE. This improves fairness when a large number of exit connections are requested, and properly signals exhaustion to the network. Fixes issue 40597; patch by Alex Xu (Hello71).

o Minor features (tests): - Avoid needless key reinitialization with OpenSSL during unit tests, saving significant time. Patch from Alex Xu.

o Minor bugfix (relay, logging): - The wrong max queue cell size was used in a protocol warning logging statement. Fixes bug 40745; bugfix on 0.4.7.1-alpha.

o Minor bugfixes (logging): - Avoid ""double-quoting"" strings in several log messages. Fixes bug 22723; bugfix on 0.1.2.2-alpha. - Correct a log message when cleaning microdescriptors. Fixes bug 40619; bugfix on 0.2.5.4-alpha.

o Minor bugfixes (metrics): - Decrement hs_intro_established_count on introduction circuit close. Fixes bug 40751; bugfix on 0.4.7.12.

o Minor bugfixes (pluggable transports, windows): - Remove a warning `BUG()` that could occur when attempting to execute a non-existing pluggable transport on Windows. Fixes bug 40596; bugfix on 0.4.0.1-alpha.

o Minor bugfixes (relay): - Remove a "BUG" warning for an acceptable race between a circuit close and considering that circuit active. Fixes bug 40647; bugfix on 0.3.5.1-alpha. - Remove a harmless "Bug" log message that can happen in relay_addr_learn_from_dirauth() on relays during startup. Finishes fixing bug 40231. Fixes bug 40523; bugfix on 0.4.5.4-rc.

o Minor bugfixes (sandbox): - Allow membarrier for the sandbox. And allow rt_sigprocmask when compiled with LTTng. Fixes bug 40799; bugfix on 0.3.5.1-alpha. - Fix sandbox support on AArch64 systems. More "*at" variants of syscalls are now supported. Signed 32 bit syscall parameters are checked more precisely, which should lead to lower likelihood of breakages with future compiler and libc releases. Fixes bug 40599; bugfix on 0.4.4.3-alpha.

o Minor bugfixes (state file): - Avoid a segfault if the state file doesn't contains TotalBuildTimes along CircuitBuildAbandonedCount being above 0. Fixes bug 40437; bugfix on 0.3.5.1-alpha.

o Removed features: - Remove the RendPostPeriod option. This was primarily used in Version 2 Onion Services and after its deprecation isn't needed anymore. Closes ticket 40431. Patch by Neel Chauhan.

Cheers! David