Inside Defense has obtained a selected acquisition report which mentions the signing of a memorandum of understanding with Australia in March for seven MQ-4Cs.
By Alex Evers (http://www.flickr.com/photos/usnavy/8906719846/) [Public domain or CC BY 2.0], via Wikimedia Commons
The same document also said Berlin will sign a letter of offer and acceptance in late 2018 for four Tritons.