Yes, these selectors are a little more specific now and we removed the opacity entirely in favor of using a solid color (there was a bug in Safari where SVG icons were clipped slightly because of the opacity).
You can remove anything you have related to opacity, and do this
.d-header-icons .d-icon {
color: #fff;
}
.d-header-icons .d-icon:hover {
background-color: #fff;
color: #001d4d;
}