Version 2.1h (June 2002)

$\bullet$ Relativistic corrections to Compton heating and cooling have been added, using a procedure based on the work of Guilbert (1986).

$\bullet$ A new format for the storage of atomic data has been adopted, resulting in smaller files, and faster read times. This change should be transparent to the user, except for considerable speeding of data loading and program startup.

$\bullet$ A new algorithm for continuum transfer has been adopted, outward only transfer. This gives better energy conservation overall. A new column has been added in the log file output, labeled `h-c', it tells the percent error in total energy conservation in the radiation field, i.e. total emitted - total absorbed.

$\bullet$ A new algorithm has been adopted for solving the statistical equilbrium, in place of LU decomposition. The algorithm involves an iterative solution to a simplified set of equations, and is described by Lucy (2001). This change should result in fast execution for models involving iron and other heavy elements, but will otherwise be transparent to the user.

$\bullet$ Various changes to atomic data, including increase in size of data file and addition of a new data type, for excitation of Fe XIX using data from Bhatia.

$\bullet$ Various minor inconsistencies and errors have been corrected, including spurious recombination emission to multiply excited levels.

$\bullet$ Standard output in the log file has been extended to include a list of the strongest absorption lines, and emission and absorption edges.

$\bullet$ Also, a new output file, xout_rrc1.fits, is created which contains a fits format list of the RRC strengths.