Regular warnings about CDR in log files

Asterisk version: 13.11.2
FreeePBX version: 13.0.189
CDR Reports Module:

Regularly getting the message at least once every 15mins, but often more in our Asterisk logs.

[2016-10-25 15:04:19] WARNING[13918]: func_cdr.c:377 cdr_write_callback: CDR requires a value (CDR(variable)=value)

Is this anything to be concerned with?

No, this is not a functional issue. I believe this is resolved in newer versions of core

ok thanks. currently on core, I’ll keep an eye out for any changes in the notes about this in subsequent releases.