Now much heap needed?

[I-AM-ENGINEER]

I writing firmware for my rnode, but i got high memory restriction (max possible for RNS 100kB). So what acceptable minimum of heap usage and what options for reduce it? For now i got heap overflow with few minutes of run.

[attermann]

Definitely suggest using the latest master branch. This has many memory and storage optimizations. Most significantly, the path table has been mostly moved from heap to flash, so as long as you have sufficient flash storage you can store many more paths with much less heap.
Also take a look at the "Memory Management Build Options" in the README for more details about memory optimization.