eBook app development is almost a dead field, but after years of only being able to report on new features in the Kindle apps, I am pleased to report that multiple Epub3 apps have been released in under a month.
A couple weeks ago EDR Lab released the first alpha version of its app for Windows, macOS, and Linux, and now I can report that similar apps have been released for Android and iOS.
Released last month, Lea Reader is an Android app that uses the open source Readium SDK as the core of a custom and easy-to-use Android SDK. The app has basic features like management of personal book collections, bookmarks, annotations, and full-text search, and supports both reflowable and fixed-layout ebooks.
This is an evolving app and it will get many new options in the coming months such as Dropbox, Google Drive, and iCloud integration. You can find the app in Google Play.
Just released this week, R2 Reader is an iOS app from EDRLab. According to the listing:
This free reading application demonstrates the power of the open-source Readium-2 architecture for accessing Epub and Epub3 publications. It is compatible with Readium LCP, the non-proprietary and user friendly solution for distributing protected publications. It supports OPDS feeds, and therefore allows users to access easily a multitude of free ebooks from multiple providers.
Edit: R2 Reader also supports the new Readium DRM. No one sells ebooks with this DRM, but you can test it here.
You can find R2 Reader in iTunes.