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Release V1.44

V1.44 was released on 2022-Aug-29 and is the current stable version. You can download the release ZIP file (4 MB):

Changes from V1.43

  • Limited mainboard LED flashing to three flashes after reset.
  • Reduced key repeat timeout from 100 ms to 50 ms.
  • Improved mate search mode.
  • Improved general performance.
  • Improved pawn hash collision handling.
  • Fine-tuned pruning and eval.
  • Removed null move threat move.
  • More late move reductions.
  • Fixed legality checks in the book tool (no engine impact).

UCI versions

  • Improved FEN parser for incomplete FENs.
  • CPU throttling has an additional activation checkbox.


  • The Android build chain has been updated from NDK r23 to r23c.

Known issues

All versions

  • Capturing a castling enabled rook and then recapturing with another rook keeps the castling rights.

Embedded target

  • The firmware is not compatible with the Olimex H405 mainboard variant that has a GigaDevice GD32F405 controller instead of an STMicroelectronics STM32F405.

Note: issues are fixed with new releases only – there are no backports. However, if an issue is found, it will be listed for the previous releases where applicable.