TriggeringInstruction/FIX.5.0+

Content of Component TriggeringInstruction

TagText	FieldName or ComponentName	Required	Description
1100	TriggerType		Required if any other Triggering tags are specified.
1101	TriggerAction
1102	TriggerPrice		Only relevant and required for TriggerAction = 1
1103	TriggerSymbol		Only relevant and required for TriggerAction = 1
1104	TriggerSecurityID		Requires TriggerSecurityIDSource if specified. Only relevant and required for TriggerAction = 1
1105	TriggerSecurityIDSource		Requires TriggerSecurityIDSource if specified. Only relevant and required for TriggerAction = 1
1106	TriggerSecurityDesc
1107	TriggerPriceType		Only relevant for TriggerAction = 1
1108	TriggerPriceTypeScope		Only relevant for TriggerAction = 1
1109	TriggerPriceDirection		Only relevant for TriggerAction = 1
1110	TriggerNewPrice		Should be specified if the order changes Price.
1111	TriggerOrderType		Should be specified if the order changes type.
1112	TriggerNewQty		Required if the order should change quantity
1113	TriggerTradingSessionID		Only relevant and required for TriggerType = 2.
1114	TriggerTradingSessionSubID		Requires TriggerTradingSessionID if specified. Relevant for TriggerType = 2 only.

Notes

Please post comments, clarifications, examples here. Click on the edit button on the right and away you go! 

Don't forget to refer to the FPL Discussion Groups to back up anything you write.
You will often find the authoritative statements on matters of FIX specification interpretation there.
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.