ISO 19115-1:2014 -- Geographic Information -- Metadata was released in 2014 as a new international standard to replace ISO 19115:2003 as the primary metadata standard in the 191** suite of standards for geographic metadata and services. ISO 19115-1 describes the information content required for describing geographic information and services. With only a few exceptions, this revised standard expands upon the descriptive capacity of ISO:19113:2003.
NOAA's Environmental Data Management Wiki and NASA's Earth Data Wiki provide summaries of the changes made to the ISO standards during this revision.
The NASA Earthdata Wiki provides a detailed yet readable description of ISO 19115-1 and the 191** suite of standards.