Collation performance is improved.
The collation implementation will continue to change for ICU 1.8 according to the collation design document.
Improved performance of parsing and formatting of dates and numbers
Improvements in the ISO-2022 implementation
Bug fixes, more stable, and support for standard country variants:
ISO-2022-JP (incl. -1, -2)
ISO-2022-CN (incl. -EXT)
ISO-2022-KR
Support for GB 18030
Basic support for UTF-32 (no ucnv_getNextUChar(), incomplete offset handling)
Support for the HZ encoding
Converter fallback semantics modified and .ucm mapping files updated with precise roundtrip/fallback indicators
ICU library names include the version number for better coexistence of different installed ICU versions on a single machine
The code libraries contain the two major/minor version digits
On Windows, they also contain a 'd' for the debug versions
The icu data file contains the ICU version and a letter for the data configuration (ASCII/EBCDIC, big-endian/little-endian)
ICU client code links with .lib files/object symlinks without the version number for easier future updates
Debian packaging
The API documentation is improved.
