The free version of this new edition is now available at

This new edition has been the occasion to overhaul the presentation in
many places, but its main purpose is the update to the new C standard,
C23. The goal was to publish this new edition of Modern C at the same
time as the new C standard goes through the procedure of ISO
publication. The closest approximation of the contents of the new
standard in a publically available document can be found here.