Fire 5 11/14/2016 deeper search several new eval clauses pst, eval, and search parameter fine tuned via SPSA UCI contempt parameter added Syszygy 50-move rule UCI parameter added chess960 support added large increase in playing strength
Fire 5 is packed with MPRESS x64 (exe / dll) - v2.12 ^ -> [v2.19] - MATCODE compressor for executables (C) 2007.2012, MATCODE Software. The file unpacked show that Fire 5 is clearly an Stockfish derivative!
... I add: changing some parameters in stockfish's code, which drastically reduce the strength of the engine, you can escape at the sim test. This thing was found in an engine still "private", called Hypnos by Marco Zerbinati. The same procedure, in my opinion, is made on Fire 5.