Starting soon WWE will stop the branding of referees and all refs will wear the same shirts (likely the traditional black & white stripes), and only two refs will be going out on the road for Raw & Smackdown House Shows rather than three.
Whether this will lead to any refs being released is unknown.
Some refs also work on ring crews. Mike Posey & Charles Robinson are examples. It is possible they could be booked on some shows only as ring crew now rather than as ring crew and as refs too, as ref pay falls under the talent budget and ring crew pay falls under a different budget.
Before this decision, RAW Referees wore the traditional black & white striped shirts. SmackDown Refs wore the blue & black striped shirt (with blue shoes). ECW Refs wore black shirts with stripes.