Hi,
In version 8.4 it is not needed to have RTI to use xxxFieldMatrix functions. I see you moved to 8.3 2017-05-05 and you do not have the message anymore.
If you want to update I suggest to do it to 8.4 to avoid the message, in 8.4 you need RTI only if you are using the next functions:
SendWebRequest
SendWebRequest2
SendWebRequest3
SendRawWebRequest
SendAsyncWebRequest
SendAsyncRawWebRequest
SendAsyncTCPRequest
Regards.