To make life easier for me and everyone else I have a constantly updated list of the latest Apple developer releases right here! No more searching the developer portal every Monday to check. Note that recently Apple changed from separate release download pages to one single one with the exception of Swift downloads. Since I do not know if this change is permanent, I went ahead and added a link for each.
Apple Release Versions
|macOS High Sierra||10.13.6||Download|
Apple Pre-Release Versions
|macOS Mojave||10.4 Beta 11||Download|
|macOS Server||5.7 Beta 4||Download|
|Classroom for Mac||1.0 Beta 4||Download|