We are hearing rumors from some of the state departments of education that the CCSS are going to be revised to include letters for each cluster? Just wondering if this is a rumor or a fact.
The standards themselves are not being revised, but CCSSO has adopted a way of referring to them that includes uppercase roman letters for the clusters, e.g. 2.MD.A.1. You can read about this at the main standards website, corestandards.org.