I think I've worked it out, try this
for normal icon - body[data-pageapp="forums"] .ipsItemStatus.ipsItemStatus_large.cForumIcon_normal
to remove the old icons - body[data-pageapp="forums"] .ipsItemStatus.ipsItemStatus_large > i, .ipsItemStatus.ipsItemStatus_large.cForumIcon_normal > i {
for read icons - body[data-pageapp="forums"] .ipsItemStatus.ipsItemStatus_large.ipsItemStatus_read {
and then for mobile -
body[data-pageapp="forums"] .ipsItemStatus.ipsItemStatus_large.ipsItemStatus_read, body[data-pageapp="forums"] .ipsItemStatus.ipsItemStatus_large.cForumIcon_normal
BostonBob reacted to marklcfc in Theme Tip: Replacing forum icons with images