We are speaking about moral teachings not traditions Faz.

Your actual phrase was 'authentic Catholic teachings cannot change'.

I think that the authenticity of Catholic teachings on capital punishment cannot be reasonably questioned given its history.

I think that the moral implications of this teaching, given that it is about life and death, cannot be reasonably understated.

Even taking your statement about 'development' at face value, it's not a term that's consistent with 'cannot change'. 'Development' is by its nature 'change'.