Just got this from David Monti:
By a 133-42 vote, the IAAF Congress delegates (in Helsinki) overwhelmingly endorsed a provision put into effect at April's IAAF Council meeting that requires athletes switching nationalities to wait three years from the date of acquiring new citizenship before they can compete for their adopted countries. Previously, the period of ineligibility began from the last time an athlete represented his/her country in international competition.
IAAF Council still reserved the right to evaluate cases on an individual basis, which could reduce the waiting period to one year, or even less, depending on the circumstances of each case and pending any agreements between the relevant federations.
The Congress narrowly turned down a proposal to make the waiting period 6 years by a 90-80 vote.