Sequence incrementing is disabled for the following commands, but the SMPP v3.4 spec requires them to have a unique sequence number:

• BindTransmitter (ref)
• BindReceiver (ref)
• BindTransceiver (ref)
• DeliverSM (ref)
• Unbind (ref)
• EnquireLink (ref)

Currently I am facing an issue with an SMSC for this.

If you are interested, I will send pull requests for these changes.