Maapi Erlang does not have save_config

I am using basic version of ConfD. And I code with Erlang. I can find maapi_save_config in C CPI, but can not in Erlang API.

Is the Erlang API not updated follow C API or this Erlang API is not supported in free version of ConfD?

Some C API functions indeed do not have its Erlang API counterparts, this is one of them. There is currently a discussion if they should be added, but even if they are, I do not expect they will be available soon.

So is this also the situation for java and python API? And only C API currently contains most of necessary functions?

Python API is based on C, and whatever is available in C API is in some form available in Python too. Java is different, but as far as I know it is also complete.