Error when loading shared library - stringini()

On a Linux 64 bits, R.3.1.2, with tidyr() loaded.

gabx at hortensia [R] separate(rawStats, 'toto')
Error in dyn.load(file, DLLpath = DLLpath, ...) :
  unable to load shared object
'/developement/language/r/library/stringi/libs/stringi.so':
  libicui18n.so.54: cannot open shared object file: No such file or directory
----------------------------------------------------

When trying to upgrade stringini(), it is not available for 3.1.2

My box run :icu 55.1-1 & :lib32-icu 55.1-1

If I am right, I need to downgrade to 54 to be able to run separate()
from tidyr package? Or is there any other way?

Thank you for hint.

google.com/+arnaudgabourygabx