Abstract
The information content of a crystal structure as conceived by information theory has recently proved as an intriguing approach to calculate the complexity of a crystal structure within a consistent concept. Given the relatively young nature of the field, theory development is still at the core of on-going research efforts. In this work we provide an update to the current theory, improving the formulas that evaluation of crystal structures with partial occupancies as frequently found in disordered system is feasible. To encourage wider application and further theory development we incorporate the updated formulas in crystIT (crystal structure & Information Theory), an open-source python-based program that allows for calculating various complexity measures of crystal structures based on a standardized *.cif file.