All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It is not permissible to exclusively designate the last Wednesday of the month of Safar for fasting or for any particular supererogatory acts of worship as this is allocating a particular act of worship to a particular time without religious evidence, and this is an innovation as previously discussed in Fatwa 17613.
Allaah Knows best.