The 5.7.4 changelog begins with the following, so I felt it appropriate to include it here as well.
“This release is dedicated to the memory of two young engineers of the MySQL Engineering family, Astha and Akhila, whom we lost while they were in their early twenties. This is a small remembrance and a way to recognize your contribution to the 5.7 release. You will be missed.”
As for the fixes, there are quite a few, which is to be expected in such an early milestone release.
The main highlights for me were:
Of course, there were many, many more fixes/updates (InnoDB being #1, Replication #2, and Partitioning #3 with most fixed bugs), so be sure to read through the full changelog. And if you are running a previous version of *5.7*, then definitely plan on upgrading to this latest 5.7.4.
Hope this helps.