From FIXwiki

FIX Message Logout (MsgType=5)

MsgType	FIX Specification	First introduced	Deprecated
MsgType=5	Session messages - Session	FIX.2.7

The logout message initiates or confirms the termination of a FIX session. Disconnection without the exchange of logout messages should be interpreted as an abnormal condition.

Before actually closing the session, the logout initiator should wait for the opposite side to respond with a confirming logout message. This gives the remote end a chance to perform any Gap Fill operations that may be necessary. The session may be terminated if the remote side does not respond in an appropriate timeframe.

After sending the Logout message, the logout initiator should not send any messages unless requested to do so by the logout acceptor via a ResendRequest.

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Notes

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