I don't believe the IAAF changed anything.
Well then, perhaps you should review the rules.
RULE 147 (IAAF Competition Rules 2012-2013, pg 138)
For all competitions held completely in the stadium, mixed events between
male and female participants shall not normally be permitted.
However, mixed stadium competition in Field Events and in races of
5000m or longer may be permitted in all competitions except those held
under Rules 1.1(a) to (h). In the case of competitions held under Rules
1.1(i) and (j) such mixed competition shall be allowed in a particular
competition if specifically permitted by the relevant Area governing body.
IAAF World Championship Qualifying website:
Performances achieved in mixed events between male and female participants
(see Rule 147) will only be accepted under the following circumstances:
o For all field events and races of 5000m and over held completely in the
stadium the results will be:
- Automatically accepted if achieved at National Permit competitions
- Accepted only with the Area Association's approval if achieved at
competitions under IAAF Rule 1.1 (i) and (j)
- Never accepted if achieved at competitions conducted under IAAF
Rule 1.1 (a) to (h)
o For road races (marathons and race walks) the results will always be
From Duffy Mahoney @ USATF:
5,000 and 10,000 meter races, which are mixed gender, and held inside a stadium – and which are USATF sanctioned – will be acceptable for qualifying for U.S. and World Championships meets.