The RDP Classifier, a widely used machine learning tool for taxonomic classification of prokaryotic and fungal sequences, has been updated to incorporate newly described taxa and recent changes in prokaryotic nomenclature. The RDP taxonomy, now at training set No. 19 (2023), includes 24,642 sequences from 19,074 species and 3,903 genera, representing a 13.8% and 20.6% increase in species and genera, respectively, compared to the previous release. The update primarily uses data from the International Journal of Systematic and Evolutionary Microbiology, the List of Prokaryotic names with Standing in Nomenclature, and public sequence repositories. The RDP Classifier (version 2.14) has been enhanced with cross-validation testing and the ability to adjust assignment counts based on 16S gene copy number information. These updates aim to improve the accuracy and reliability of taxonomic classifications, particularly in microbiome studies.The RDP Classifier, a widely used machine learning tool for taxonomic classification of prokaryotic and fungal sequences, has been updated to incorporate newly described taxa and recent changes in prokaryotic nomenclature. The RDP taxonomy, now at training set No. 19 (2023), includes 24,642 sequences from 19,074 species and 3,903 genera, representing a 13.8% and 20.6% increase in species and genera, respectively, compared to the previous release. The update primarily uses data from the International Journal of Systematic and Evolutionary Microbiology, the List of Prokaryotic names with Standing in Nomenclature, and public sequence repositories. The RDP Classifier (version 2.14) has been enhanced with cross-validation testing and the ability to adjust assignment counts based on 16S gene copy number information. These updates aim to improve the accuracy and reliability of taxonomic classifications, particularly in microbiome studies.