Yes - and once the extensions from the 4.x repo are confirmed working they can be copied to the 5.x repo.
Note:
* libpng was updated from tc-4.x to tc-5.x, most 4.x extensions that do not depend on libpng will work without problems in 5.x
* libpng, libjpeg and imlib2 were taken out of the base and several extensions (graphics-libs-1, Xprogs, Xlibs, Xorg) were refactored from tc-4.x to tc-5.x. This means the dep files of extensions from the 4.x repo might need adjusting to work in tc-5.x