:This, which appears to be official, states the federal observance of the inaugaration will be the following day, Jan. 21, but does not specifically say the the ceremony itself will be moved - it only says "Inauguration Day.....falls on a Sunday." I could not find reliable sources from a Google search that stated the ceremony will be held on the the 21st. Until such sources can be found to verify that the inauguration will be held on a different date than than Jan. 20, it is best to leave it as is.