Feb. 23 newvers.sh starts to say 5.4-PRERELEASE
Mar. 2 RELENG_5 code freeze begins
Mar. 4 Public test release build called 5.4-PRERELEASE
Mar. 16 Branch RELENG_5_4, unfreeze RELENG_5
Mar. 18 5.4-RC1
Mar. 25 5.4-RC2
Apr. 4 5.4-RELEASE
You can watch the schedule and open issues pages as the release engineering process continues.