Until now the storage ring lattice had 16 identical superperiods. The modifications underway will break the symmetry of the lattice for the first time. This may enhance the sensitivity of the machine to magnet imperfections, however, studies using the flexibility power supplies on ID6 and ID11 showed that the lifetime should not be affected. The optical functions in ID23 will be close to the present values, with a vertical β increased from 3 m to 3.5 m to better match the new length of the straight section.