This provides zip archives of releases of the CIL-ASTRA plugin for the use of the ASTRA Tomography Toolbox within the Core Imaging Library (CIL), for the purpose of offering permanent DOI-linked records. The specific version supporting the Transactions of the Royal Society A papers: Core Imaging Library Part I: a versatile Python framework for tomographic imaging Core Imaging Library Part II: multichannel reconstruction for dynamic and spectral tomography is release v21.0.0, which is a specific version of this Zenodo record, which is directly available at https://doi.org/10.5281/zenodo.4746179 CIL and CIL-ASTRA are maintained at https://github.com/TomographicImaging/CIL https://github.com/TomographicImaging/CIL-ASTRA from where all releases can be accessed directly. Installation through Anaconda is recommended, see instructions on GitHub and www.ccpi.ac.uk/CIL Requires the following versions: ASTRA 1.9.9_dev CIL >= 21.0.0 The author list used here consists of the main CIL developers in alphabetical order. A number of other people contributed to CIL, see Notice.txt in CIL.