Alain,

chessfriend Hans Jürgen Schäfer send me a nice test for the Super Expert/Forte C versions:

Phantommatt
Is Qxc6 mate?

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h

(9/9) FRC FEN-Editor © SMIRF Ver. 3.0.0 / License: Stefan Ottow

2q4r/1kp4p/1pbp2p1/8/P1Q5/1P3NP1/2PK2BP/8 w - - 0 1

My Super Forte C V 1.2 (Level 7 Sel 5) plays after a few seconds Qxc6 with mate in 3 (this is true in fact, IF black in taking the queen!!), whereas the Super Expert V3.6 plays the same move but with an eval of +2.38 and the expected answer of Kb8. For me it looks more like a bug fix in the routine for the mate search rather than a program improvement.

Anyway, you should check V3.5

best regards
Stefan