NVDA 2016.1 has arrived. We tested it with the Acapela TTS for NVDA release 1.21 and the two work together splendidly.
You can download NVDA 2016.1 here: http://www.nvaccess.org/download/
You can learn more about what’s new in 2016.1 here: http://www.nvaccess.org/files/nvda/releases/2016.1/nvda_2016.1_changes.html