​When can sequence numbers be reset?

Gemini runs the server side of the FIX connection ("acceptor"). Gemini never resets sequence numbers on the server side during the logon workflow unless the client explicitly requests it.

The client ("initiator") can reset sequence numbers during Logon <A> by setting ResetSeqNumFlag <141> to Y.

Gemini recommends that client consider configuring the FIX initiator to automatically reset sequence numbers under the following conditions:

• logon
• logout
• disconnect
• error

While synchronizing sequence numbers after a replay, the client may send a Sequence Reset <4> with GapFillFlag <123> = Y in lieu of a replay.