Use at your own risk. You should backup your presets if you need/want to roll back.
Mark I/II:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/beta/axefx2_18p00_public_beta.zip
XL:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/beta/axefx2_xl_18p00_public_beta.zip
Mark I/II:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/beta/axefx2_18p00_public_beta.zip
XL:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/beta/axefx2_xl_18p00_public_beta.zip