Stockfish 16.1

Official release version of Stockfish 16.1

Bench: 1303971

---

Stockfish 16.1

Today, we have the pleasure to announce Stockfish 16.1. As always, you can
freely download it at https://stockfishchess.org/download and use it in the GUI
of your choice[1].

Don't forget to join our Discord server[2] to get in touch with the community of
developers and users of the project!

*Quality of chess play*

In our testing against its predecessor, Stockfish 16.1 shows a notable
improvement in performance, with an Elo gain of up to 27 points and winning over
2 times more game pairs[3] than it loses.

*Update highlights*

*Improved evaluation*

- Updated neural network architecture: The neural network architecture has
  undergone two updates and is currently in its 8th version[4].
- Removal of handcrafted evaluation (HCE): This release marks the removal of the
  traditional handcrafted evaluation and the transition to a fully neural
  network-based approach[5].
- Dual NNUE: For the first time, Stockfish includes a secondary neural
  network[6], used to quickly evaluate positions that are easily decided.

*UCI Options removed*

`Use NNUE` and `UCI_AnalyseMode`[7] have been removed as they no longer had any
effect. `SlowMover`[8] has also been removed in favor of `Move Overhead`.

*More binaries*

We now offer 13 new binaries. These new binaries include `avx512`, `vnni256`,
`vnni512`, `m1-apple-silicon`, and `armv8-dotprod`, which take advantage of
specific CPU instructions for improved performance.
For most users, using `sse41-popcnt` (formerly `modern`), `avx2`, or `bmi2`
should be enough, but if your CPU supports these new instructions, feel free to
try them!

*Development changes*

- Updated testing book: This new book[9], now derived exclusively from the open
  Lichess database[10], is 10 times larger than its predecessor, and has been
  used to test potential improvements to Stockfish over the past few months.
- Consolidation of repositories: Aiming to simplify access to our resources, we
  have moved most Stockfish-related repositories into the official Stockfish
  organization[11] on GitHub.
- Growing maintainer team: We welcome Disservin[12] to the team of maintainers
  of the project! This extra pair of hands will ensure the lasting success of
  Stockfish.

*Thank you*

The Stockfish project builds on a thriving community of enthusiasts (thanks
everybody!) who contribute their expertise, time, and resources to build a free
and open-source chess engine that is robust, widely available, and very strong.

We would like to express our gratitude for the 10k stars[13] that light up our
GitHub project! Thank you for your support and encouragement – your recognition
means a lot to us.

We invite our chess fans to join the Fishtest testing framework[14], and
programmers to contribute to the project either directly to Stockfish[15] (C++),
to Fishtest[16] (HTML, CSS, JavaScript, and Python), to our trainer
nnue-pytorch[17] (C++ and Python), or to our website[18] (HTML, CSS/SCSS, and
JavaScript).

The Stockfish team

[1] https://github.com/official-stockfish/Stockfish/wiki/Download-and-usage#download-a-chess-gui
[2] https://discord.gg/GWDRS3kU6R
[3] https://tests.stockfishchess.org/tests/view/65d666051d8e83c78bfddbd8
[4] https://github.com/official-stockfish/nnue-pytorch/blob/master/docs/nnue.md#sfnnv8-architecture
[5] af110e0
[6] 584d9ef
[7] c53d2ec
[8] 536d692
[9] official-stockfish/books@426eca4
[10] https://database.lichess.org/
[11] https://github.com/official-stockfish/
[12] https://github.com/Disservin
[13] https://github.com/official-stockfish/Stockfish/stargazers
[14] https://github.com/official-stockfish/fishtest/wiki/Running-the-worker
[15] https://github.com/official-stockfish/Stockfish
[16] https://github.com/official-stockfish/fishtest
[17] https://github.com/official-stockfish/nnue-pytorch
[18] https://github.com/official-stockfish/stockfish-web

src/misc.cpp

@@ -75,7 +75,7 @@ namespace Stockfish {
 namespace {
 
 // Version number or dev.
-constexpr std::string_view version = "dev";
+constexpr std::string_view version = "16.1";
 
 // Our fancy logging facility. The trick here is to replace cin.rdbuf() and
 // cout.rdbuf() with two Tie objects that tie cin and cout to a file stream. We