I'm working on a major update to utax for v8.1 which I hope to post in the next few weeks (writing in mid-April 2015). The updated algorithm will allow more flexibility in the taxonomy (e.g., varying levels in the tree and levels which do not have names) and will allow users to train parameters on their own reference data.
I won't be sending an email notification when v8.1 is
posted. I only send emails for major version changes (no spam!). If you want to
know when v8.1 is posted, you can use a service like
changedetection.com to monitor changes
to the USEARCH download page (/usearch/download.html).