If you visit the page and search for that text, you will find it is on there, under the information about the new filtering :) The release posts are where such valuable info is given, so always worth a read through.
As for which to use, it is up to you - we always recommend the Corona High Quality Denoiser for finals, which works great with the new high quality filtering. The AI denoisers are provided as options, for the user to decide if they want to use them (but they are not what we recommend, since the Corona Denoiser is the most accurate, uses the most information from the scene to do its job, etc. - this is why it takes longer to do the job, though). So, if for some reason speed is your primary concern rather than quality, you might want to use one of the AI denoisers - but in those cases, you will have to disable the new high quality filter.