Apple isn't in the habit of releasing public betas of new OS versions. In fact, it's been over a decade since it has.
The public will gain access to a beta build of Apple's latest OS X overhaul by the end of July, with the fourth version of the developer preview arriving today, sources told the site. (Update: OS X Yosemite Preview 4 did arrive to developers after we first posted this story.)
Apple previously said a public preview of Yosemite would take place by the end of summer.
The same sources told the site that a new developer preview of iOS 8 will arrive today as well, though the report is tempered with a warning that "these plans are fluid" and might change. (Update: It did indeed arrive to developers).
Because plans could change, the OS X Yosemite public beta might be pushed back to early August because Apple reportedly wants to make sure the OS is ready for the mass consumption.
Yosemite brings a number of changes to OS X, including interface tweaks, better Spotlight search, increased iOS synchronization, and improvements to various apps.
The completed version of OS X Yosemite is scheduled to arrive this fall.