Today I purchased RT CLE - BOS in K class via our travel agent for this coming Tue - Wed (7/11 - 7/12). The tickets were booked at 7:33 PM EST.

At 7:45 PM EST, I immediately received confirmation of an upgrade on both flights. Wild! Don't get me wrong, I am thrilled and am NOT complaining, but I thought EUA only ran at 12 AM CST each day and only if I bought a Y fare would I get it right away.

Interesting.