For a woman in Iddah period following the death of her husband necessary to wear only white clothes?

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.

We do not know of any evidence that requires a woman who is in her waiting period after divorce or as a widow to wear clothes of a particular colour, white or otherwise. If one believes that this is a religious act, then it is an innovation in religion. But a woman in her waiting period should avoid clothes of beauty or adornment.

Allaah knows best.