Doing a search on Google to find the purpose of the Order bit in the 802.11 header (subfield of the frame control field) only provides a generic (not helpful) explanation of how it's used for stict ordering of the fragments/frames. Fine, but what does that really mean and when would the process/OS/adaptor request or need this? I've seen the Order bit turned on in control, data and management frames using wireshark but was not able to decipher why it was set.
This bit indicates that this frame is being sent using the strictly-ordered service class.
The strictly-ordered service class is defined for users that can't accept change of ordering between Unicast frames and multicast frams. The only known protocol that would need this service class is DEC's LAT. Very few people are using DEC's LAT now, so actually this bit doesn't have much meaning.