While being a fork from PIVX we have the opportunity to use and improved new and existing features directly from them. Our core wallet had a lot work done regarding security and stability.
The following updates and upgrades from PIVX have been added to Wispr:
https://github.com/PIVX-Project/PIVX/blob/master/doc/release-notes/release-notes-3.2.0.md
https://github.com/PIVX-Project/PIVX/blob/master/doc/release-notes.md
Additional (Wispr related) patch notes:
- General cleanup of code, added more documentation etc.
- Removed unused a lot of old (prev versions) code.
- Big cleanup of dependencies.
- Refactored all code to C++11.
- Added all kinds of back-ported bitcoin-core features.