Read Me for the updated country definitions used for CRU CY. CRU CY presents monthly, seasonal and annual series, spatially averaged over individual countries. It is based on the CRU TS high-resolution multivariate gridded data set and is released in step with it. The definitions of country names and boundaries have now been updated to reflect geopolitical changes of the past two decades. Some minor corrections were also made. The vast majority of country series are unchanged. However, in some cases countries have been divided, renamed, or subsumed into others: 1. Sudan separated into 'Sudan' and 'South Sudan' 2. Indonesia separated into 'Indonesia' and 'East Timor' 3. Yugoslavia separated into 'Kosovo', 'Montenegro' and 'Serbia' (this also affected Albania and Macedonia) 4. Federated States of Micronesia Caroline Islands, Marianas and Truk reallocated to 'Yap State', 'Chuuk State', and 'Pohnpei and Kosrae' (also affects Marshall Isl) 5. Cabinda made part of Angola 6. Zaire renamed 'DR Congo' 7. Antigua and Barbuda joined to form 'Antigua and Barbuda' 8. St Kitts renamed 'St Kitts and Nevis' 9. Surinam renamed 'Suriname' 10. Moldavia renamed 'Moldova' Previous versions of CRU CY (v3.25 and v4.01) were made available in both configurations: these are still available for comparisons to be made. Subsequent releases all use the new definitions.