For some reasons ^1,2,3, most distributions of ICU are compiled using the symbol renaming feature (a suffix containing the ICU version number is added to every symbols in shared objects).

It makes the task of creating a generic Crystal binding more difficult since ABIs of different versions of ICU are 100% incompatible.

For the moment the lib_icu binding has been generated against the version 52 of ICU making it incompatible with any other version of the library.