Hello, There is the an issue, MbedTLS don't have backward compatibility with its previous versions. So, MbedTLS APIs need to be changed.
I noticed this change after trying to port libSRTP for Zephyr RTOS. Here is the PR to do that. Also I tried to add support for Zephyr RTOS in libSRTP as well, here is its related issue. If you are out of time, I can help.