Is a divorce that was issued by sending a WhatsApp message to the wife's sister valid, regardless of whether the wife was informed of the divorce or not, knowing that the wife is pregnant?

Scholars differ on the ruling of divorce written in mobile messages and the like, whether it is like uttering it or a metaphor (kinayah). If the husband explicitly writes the divorce of his wife and intends it, the divorce occurs immediately upon writing, even if the wife does not know about it. Al-Sarakhsi and Ibn Nujaym from the Hanafis, and the Mudawwanah from Imam Malik, reported that informing the wife is not a condition for the divorce to take effect. Furthermore, pregnancy does not affect the occurrence of divorce.