-TC=4'+2"
-Hash=256 MB
-GUI: Arena 3.5.1
-Books: IM_4mvs.abk (8 plies book) for both engines
-default settings for both engines
-1 thread-CPU=Intel i5-7400-3GHz (Kaby Lake)
-OS: Windows 10 Home
-6-men Syzygy bases (only for Halogen9-x64-pext-avx2)
Winter 0.9 x64 has 3158 Elo points (CCRL Blitz).
Halogen9-x64-pext-avx2 has around 3102 Elo points. +106 Elo points face to Halogen 8.1 x64 (in my single match test - 100 games).
Halogen 8 x64 has 2821 Elo points (CCRL Blitz).
Halogen 8.1 x64 has 2996 Elo points (CCRL Blitz).
Halogen 9 x64 has 3154 Elo points (CCRL Blitz).
CCRL Blitz rating list shows +158 Elo points. Only two explanations are possible:
-static error (just one opponent, only 100 games);
-Winter is a "bad" engine for Halogen.
The trend is upward, anyway. Congratulations !