The Office 365 Roadmap website (roadmap.office.com) now allows an export to Excel for download.
Each item also includes "First Added" and "Last Modified" dates.
With a simple download and filter, you can easily determine which features are new and which ones have been updated since the last time you reviewed. Also, as an Excel file, it can be easily imported into other systems for additional actions.
I had some fun with the download. We are running Office ProPlus and for some reason, it didn't like the .xls version of the file it wanted to download. I attempted some other formats with save as, but the formatting was bad. I was finally able to download it, but had to open Excel first to access the file. Looks interesting and I am looking forward to looking around the file, but probably won't use this feature much in the future.