The generator matrix

 1  0  1  1  1  X  1  1  1  1  0  X  1  1  1  1  0  X  X  X  0  1  1  1
 0  1 X+1  X  1  1  0  X X+1  1  1  1  0  X X+1  1  1  1  0  X  X  0  X  0

generates a code of length 24 over Z2[X]/(X^2) who´s minimum homogenous weight is 24.

Homogenous weight enumerator: w(x)=1x^0+3x^24+8x^25+2x^26+2x^30

The gray image is a linear code over GF(2) with n=48, k=4 and d=24.
As d=24 is an upper bound for linear (48,4,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 4.
This code was found by Heurico 1.16 in 0.00152 seconds.