Maybe the simplest, most TCL way:
* keep complete vanilla set of current version (lua-5.4.tcz, lua-5.4-lib.tcz, and lua-5.4-dev.tcz)
* keep only *-lib.tcz of old version (lua-5.3-lib.tcz) because some repo applications need it
Juanito, if you decide to go with this approach, the lua-5.4.tcz already in x86_64 repo (timestamped 2023/08/17) should be fine. Please let me know if you want me to resubmit lua-5.4-lib.tcz and lua-5.4-dev.tcz built with the LFS patch, without any manually renamed files or startup scripts.
I guess the last detail would be to remove liblua.so from lua-5.3-lib.tcz, so that applications compiled in the future don't accidentally compile against the old version of the library.