Lua 5.3 is still in the "what the hell do we add" stage but you can find the source here: http://www.lua.org/work/
or windows binaries made with MinGW: https://dl.dropboxus.../lua53work2.zip
It is almost identical to 5.2 but has some major things we have all wanted like integers, bitwise operators, and utf8 support
the list is small but here are the changes from 5.2: http://www.lua.org/work/doc/#changes
Main changes:
- support for integers (64-bit by default)
- better support for small architectures ("Small Lua" with 32-bit numbers)
- bitwise operators
- basic utf-8 library
- utf-8 escapes in literal strings
- functions for packing/unpacking numbers
- userdata can have any Lua value as uservalue
- strip option in lua_dump/string.dump
- Can be used as calculator; no need to prefix with '='