Ball-Chatham Community Unit School District 5 issued the following announcement on March 4.
With the advent of "Early Release Wednesdays" this year, only four School Improvement Days are scheduled. They are: September 20, October 31, March 6, and May 1. On those days, BES and CES will dismiss at 11:05 a.m.; and GES will dismiss at 11:45 a.m.
Original source can be found here.
Source: Ball-Chatham Community Unit School District 5