First, the PMI-ACP application requires 1500 hours of experience in the past 3 years specifically on an agile project team or using an agile methodology such as Kanban, Extreme Programming (XP), Feature Driven Development (FDD), or Dynamic Systems Development Method (DSDM), Scrum (which calls itself a framework), and lean product development which is more a set of principles. If you don't have such experience for your application, put off the PMI-ACP until you do.
If you took the PMP exam before March 26, 2018, like I did, your exam was based on the 5th edition of the PMBOK Guide.
For readers here who take the PMP exam on or after March 26, 2018, it is based on the 6th edition of the PMBOK Guide. The exam content outline does not change, but the PMBOK 6th edition has appended the Agile Practice Guide, and among a bunch of changes in process names and sequence, adds a lot of discussion at the beginning of each knowledge area on agile/adaptive and hybrid approaches in addition to the predictive or waterfall approach.
I too am preparing to take the PMI-ACP this spring, after achieving my PMP July 2017 and my Professional Scrum Master (PSM) from scrum.org this week (yay!). I used a Kanban board with semi-monthly sprints at my previous job at a commercial printer, launching ecommerce web-to-print portals for big brands. And in my contract work here at OSP International, we use a similar task board to develop lessons and sample exam questions.
The PMI-ACP Exam Content Outline is remarkably different from the one for PMP. The PMI-ACP has 7 domains (which are not to be regurgitated like the PMP domain process groups) along with an Agile Toolkit consisting of tools & techniques and knowledge & skills.
From what I understand, most of the PMI-ACP questions are situational, requiring you to drink the Kool-Aid to be able to make decisions based on the Agile Mindset. This is a big difference from memorizing PMP ITTOs and definitions.