Along with fixes for known bugs, the changes made for version 2.2 mostly consist of several small additions to the science code. Changes to the control code have mostly been limited to bug-fixes.
There have also been changes made to the way JULES is compiled, due to the re-integration with the Met Office Unified Model. The Unified Model uses preprocessor directives to compile different versions of routines depending on the selected science options. For compatibility with this system, JULES will now require a compiler with a preprocessor. This should not be noticed by the majority of users - most modern compilers include a preprocessor and the Makefile deals with setting up the appropriate preprocessor options.