From FIXwiki

FIX Message Component DisplayInstruction

FIX Specification	Type	First introduced	Deprecated
Common	Block	FIX.4.4

The DisplayInstruction component block is used to convey instructions on how a reserved order is to be handled in terms of when and how much of the order quantity is to be displayed to the market.

Component Contents By FIX Version

Notes

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Don't forget to refer to the FPL Discussion Groups to back up anything you write.
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Links from FIXwiki pages to relevant discussions on the FPL site are very valuable.

For example if you were writing a clarification on how to specify the "quantity" of an order in FIX, you might add the
following relevant link, http://www.fixprotocol.org/discuss/read/f5014573, to back up your points.