Current version is 2.4 (version 2.3 was never publicly released)

* Changes since version 2.2
  + external compiler creates portable binary files that can be loaded faster
  + interface for debugging and profiling
  + new "getglobal" fallback
  + new functions for handling references to Lua objects
  + new functions in standard lib
  + only one copy of each string is stored
  + expanded documentation, with more examples

* Changes since version 2.1
  + functions now may be declared with any "lvalue" as a name
  + garbage collection of functions
  + support for pipes

* Changes since version 1.1
  + object-oriented support
  + fallbacks
  + simplified syntax for tables
  + many internal improvements