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Hi

nothing is impossible but these are the numbers:
928.610.105.16  up to 928.610.105.22 for the S4/GT series
928.610.105.24 is for the GTS series
As far as I know there are no more versions for S4/GT/GTS.

The number in the picture above looks like a .23, and there is no report of a 928.610.105.23 .

This is from the Porsche parts website, n ot saying anything about a .23 version:...
92861010500 Trägerplatte 612,80 €
92861010501 Trägerplatte 2.655,00 €
92861010504 Trägerplatte 2.655,00 €
92861010505 Trägerplatte 2.655,00 €
92861010507 Trägerplatte 561,00 €
92861010509 Trägerplatte 780,08 €
92861010513 Trägerplatte 714,81 €
92861010516 Trägerplatte 2.655,00 €
92861010517 Trägerplatte 2.655,00 €
92861010519 Trägerplatte 2.655,00 €
92861010521 Trägerplatte 2.655,00 €
92861010522 Trägerplatte 2.655,00 €
92861010524 Trägerplatte 2.655,00 €

Now here it comes: my 1992 928GTS has the 928.610.105.23 as well.  Sigh.... what have they done? No idea if .24 and .23 are compatible, I'd assume they are.
regards
Theo
1992 928gts Midnight Blue (2006-)
1988 928s4 Cherry Red (1999-2006)
The Netherlands

 

1990 CEB, click on the picture to see a full size. This picture was made by Ed Scherer, hope he doesn't mind keeping a copy here...