None of your old libraries, static or shared, can be used with a
different C library major version. For shared libraries this is not a
problem, because the filenames are different and the dynamic linker
will enforce the restriction. But static libraries have no version
information. You have to evacuate all the static libraries in
/usr/lib to a safe location.
The situation is rather similar to the move from a.out to ELF which
long-time Linux users will remember.