A new bug is introduced in UMG 7.3.0, you may get an error with the UMG-Comment module. simply install this minor upgrade to fix it.
Another bug fix is you may not be able to download a image when view permission is enabled and you are not logged in.
We forget to included a dll(zlib.net.dll) in the PA of UMG, which is used to read flash movie information. now it's included.