The Pencil Code Collaboration: Brandenburg, A., Johansen, A., Bourdin, P. A., Dobler, W., Lyra, W., Rheinhardt, M., Bingert, S., Haugen, N. E. L., Mee, A., Gent, F., Babkovskaia, N., Yang, C.-C., Heinemann, T., Dintrans, B., Mitra, D., Candelaresi, S., Warnecke, J., Käpylä, P. J., Schreiber, A., Chatterjee, P., Käpylä, M. J., Li, X.-Y., Krüger, J., Aarnes, J. R., Sarson, G. R., Oishi, J. S., Schober, J., Plasson, R., Sandin, C., Karchniwy, E., Rodrigues, L. F. S., Hubbard, A., Guerrero, G., Snodin, A., Losada, I. R., Pekkilä, J., & Qian, C.: 2021, ``The Pencil Code, a modular MPI code for partial differential equations and particles: multipurpose and multiuser-maintained,'' Journal of Open Source Software 5, 2684 (arXiv:2009.08231) . This is the current version; see the "Scientific Usage of the Pencil Code" under http://pencil-code.nordita.org/highlights/ (DOI:10.5281/zenodo.3466444) for the currently about 600 publications using the code. The code has received 32,552 commits since 2001. The latest version is available under https://github.com/pencil-code