The generator matrix

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

generates a code of length 21 over Z2[X]/(X^2) who´s minimum homogenous weight is 16.

Homogenous weight enumerator: w(x)=1x^0+347x^16+152x^18+636x^20+208x^22+499x^24+152x^26+52x^28+1x^40

The gray image is a linear code over GF(2) with n=42, k=11 and d=16.
As d=16 is an upper bound for linear (42,11,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 11.
This code was found by Heurico 1.16 in 3.32 seconds.