I am adding css border-radius in the html email. This renders fine on mail Client on Apple desktop device. However when I open same mail using webmail version on Safari or Firefox, the border-radius property is gone, it does not exist any more. There images does not render with rounded corner. However If I debug inspect element and add this property back manually, it renders fine. I think mail server sanitizer is stripping off border-radius for not so good reason. I also tried add rest of the possible ways border -radius can be specified, but nothing is allowed to browser mail. ( moz-border-radius:4px;webkit-border-radius:4px;o-border-radius:4px;)