fds in sdk14

[Stas]

I'm trying to migrate my old app based on buttonless app sdk13 to buttonless app sdk14. I solved issuie according to migrate guide remove chunk things and etc. My app works well until I add fds_init function in my main.c file.
Here's my fds_test_init function

ret_code_t fds_test_init (void)
{
		
		ret_code_t ret = fds_register(fds_evt_handler);
		if (ret != FDS_SUCCESS)
		{
					return ret;
		}
		ret = fds_init();
		if (ret != FDS_SUCCESS)
		{
				return ret;
		}
		return NRF_SUCCESS;
		}

After I comment calling of that function in my main.c the app starts work. After comment again not working. I see nothing in RTT terminal

The same code works well with sdk13

[Stas]

1. I don't know what does it means "register properly". I do it like in example code on infocenter of nordic. As I think there are not any changes in this part between sdk13 and sdk14.
2. I can't find this function. But I guess it's the same as should be, because I've changed nothing in component folder files.
3. After I step through raw ret = fds_init(); the ret is 0 in watch window while debugging.
4. I can't check this value because my program as I think doen't go into fds_evt_handler