Is Tag 35=G OrderCancelReplaceRequest [type 'G'] is supported

I am trying to implement Stop Order modify.

For this purpose using message with Tag 35=G is ideal I think.

In the rules of engament I don't see mention of Tag 35=G.

Also, I tried to send message in the following format with proper tag values as follows::

24/10/2018 02:22:51.914 Send : 8=FIX.4.4
9=161
35=G
49=ctrader.3200908
56=cServer
57=TRADE
50=QUOTE
34=3
52=20181024-02:22:49
41=592710517
11=1173682072
55=2
54=1
60=20181024-02:22:49
38=1000
40=3
99=1.30287
10=029

 

I get message with Tag 

58 = Invalid MsgType

followed by Tag 372 = G  and Tag 373 = 11.

As per FIX4.4 on FixiMate I think the message sent is in valid format. But not sure why it is flagging as "Invalid Message".

I was wondering, since you do not publish this in Rules of Engament Document your FIX server may not support it.

Please clarify.

Thanks,