Given a reference text about Hackpad, what company acquired it?

Hackpad was a web-based collaborative real-time text editor forked from Etherpad.[1]

It was used as the company wikis by multiple prominent startups of the 2010s, such as Airbnb, Stripe, and Upworthy.[2]

In April 2014, Hackpad was acquired by Dropbox.[3][4] In April 2015, it was announced that Hackpad would be released as open source[5] and source code was published on GitHub in August 2015,[6] under the Apache license 2.0.[7] On April 25, 2017, Hackpad announced that it is to shut down on July 19, 2017, permanently migrating to Dropbox Paper.[8]

Hackpad was acquired by Dropbox in April 2014.