temperature. Our approach, working from fundamental processes, means that  can be applied to such diverse regions as the corona of a star, the intergalactic medium, or the accretion disk near the supermassive black hole in a luminous quasar. As a result, the code is widely used, with nearly 200 papers citing its documentation each year. The diversity of problems it can address is a testimonial to the importance of treating the atomic physics at an elementary level.

Processor power has always limited our ability to simulate detailed microphysics. Improved computers and advances in atomic and molecular physics allow a better simulation. Improved numerical methods or coding techniques make the solutions more robust. These advancements to the fidelity of the simulation improve our insight into the inner workings of astronomical objects. Because of these changes, , like most software, goes through a development / release cycle. Our goal is to make major updates every two or three years.

This paper is a progress report on the improvements to  since the last major review, @Ferland1998, referred to as F98 in the following. Although the code’s download includes extensive documentation that is continuously updated, there has not been a recent major review. We 