By compatible, do you mean will it be able to read data?
Yes, with no heavy performance impact.
For encryption at rest what are you using....TDE?
I don't know the answer to that. As I said, the vendor's app does the encryption/decryption at the client, not on the SQL Server. So I don't know ultimately how the data is stored in SQL. I only know that I'm not being asked to set up TDE or column-level encryption at the server or database or table level.
