Patch 5.4.8 build 18291 went live on May 20, 2014 less than a week after build 18273 appeared on the PTR on May 15, 2014. Build 18224 appeared on the PTR on May 7, 2014, almost two months after the unofficially named Patch 5.4.7hotfix3 build 18019 that was released on February 12, 2014. The reasons for this hotfix build are not specifically known, but there could be an official blog upcoming detailing some related hotfixes.