(Athletes are pictured competing on Drake's blue oval at the 2012 NCAA Outdoor Championships.)
If there has been any sort of official announcement, I've missed it, but apparently the USA Track & Field Outdoor Championships will be contested at Drake Stadium in Des Moines in both 2018 AND 2019.
In January, USATF put out a release announcing Drake would host this year. Nothing about 2019 was mentioned in that release.
USATF issued this release on Thursday about meets to be televised this year by NBC and NBCSN. You have to read all the way to the bottom to see the news about the 2019 outdoor championships.