[Cppcms-users] libicu in booster

Trying to migrate a  cppcms application to bullseye debian, I am blocked 
by :

/usr/bin/ld: warning: libicuuc.so.63, needed by 
/usr/local/lib/libbooster.so, not found (try using -rpath or -rpath-link)
/usr/bin/ld: warning: libicui18n.so.63, needed by 
/usr/local/lib/libbooster.so, not found (try using -rpath or -rpath-link)

I have libicuuc but it is libicuuc.so.67.

What is the best practice to correct...?

Thanks.

PC