I am trying to add a new UDP protocol to my FreeRTOS project and reading the FreeRTOS+UDP Primer – A Step by Step Tutorial it says I must HEAP4. I need to use Heap5. Is this a true limitation?

Heap4 and Heap5 are basically the same, the latter just enables you to split the memory used as the heap across multiple memory regions. Note FreeRTOS+UDP was deprecated some time ago in favour of FreeRTOS+TCP, which can be configured for UDP only operation. The +TCP code has and continues to undergo memory safety proofs.

Thanks, I am in fact using +TCP code. I am also using +CLI and using it as an example of adding a UDP protocol since the interpretor uses a UDP socket.