In August 2023 the RDP Classifier was updated to version 2.14 using bacterial and archaeal training set No. 19. This training set includes 600 new genera and 2,500 new species over the previous version released in 2020, as well as numerous taxonomic rearrangements and adoption of new phyla names as proposed in Oren and Garrity (2021). For further details, see the release notes.
You may download the updated classifier from Sourceforge. In addition, there are species rank and QIIME2 formatted versions of the training data.
The web version of the RDP Classifier is no longer available.
Reference
Oren, A. and G.M. Garrity. 2021. Valid publication of the names of forty-two phyla of prokaryotes. Int J Syst Evol Microbiol. 2021 Oct;71(10). doi: 10.1099/ijsem.0.005056. PMID: 34694987.