This version (v2.0.0, also released to the Comprehensive R Archive Network) of the R package srppp reliably reads in XML files in the original file format that was first used by the Swiss Federal Office of Agriculture (FOAG) and in the current file format as used by the Federal Food Safety and Veterinary Office (FSVO). The current description given in the DESCRIPTION file is reproduced below: "Generate data objects from XML versions of the Swiss Register of Plant Protection Products (SRPPP). An online version of the register can be accessed at https://www.psm.admin.ch/de/produkte. There is no guarantee of correspondence of the data read in using this package with that online version, or with the original registration documents. Also, the Federal Food Safety and Veterinary Office, coordinating the authorisation of plant protection products in Switzerland, does not answer requests regarding this package."
You may also be interested in our agroscope-ch/srppphist package (https://agroscope-ch.github.io/srppphist/) containing historical registration data starting from 2011.