I think you asked almost the same question about a week ago, but in addition to what Armeen said, until PB2018 comes out, you can still use web services and pass JSON back and forth.  You can create PB/.NET SOAP services to replace  your EA Server tier and pass JSON (including dw state).  Then when PB2018 comes out, you can switch them to REST services, but you'll already be ahead of the game with the SOAP implementation.  Another option, although more work would be a rewrite of the EA Server code to java/REST, and still pass JSON.  I think you still have my email if you need help.

Hi Sally, 

PB 2017 supports calling server-side business objects as REST Web APIs.  New REST client, JSON data handling, and data encoding features are all included in the latest PB 2017 R3. 

The way you move binary data back n' forth over REST Web APIs is to use Base64 data encoding.  In fact, we have a short blog about this topic: https://community.appeon.com/index.php/blogs/recent-blogs/base64-your-new-binary-friend

You will eventually need to migrate off of EAServer, and your two lowest-cost options would be:

1. Move the EAServer NVOs back to the client-side (i.e. go back to a traditional 2-tier client/server app)

2. Port your EAServer NVOs to C# REST Web APIs with PB 2018: https://www.appeon.com/pb2018.html

Regards,
Armeen