Complex sentence: Unveiled on June 25,2014, a developer preview of the OS was released the next day for select Google Nexus devices, it is expected to be released in late 2014; its formal version number and official codename have not yet been announced.
Split into simpler sentences: Unveiled on June 25,2014, a developer preview of the OS was released the next day for select Google Nexus devices. Its formal version number and official codename have not yet been announced.