The IRS has updated the Opportunity Zones Frequently Asked Questions document to reflect that both 2017 and 2018 gains invested in Opportunity Zone Funds are eligible for deferral. If 2017 taxes were already filed, the taxpayer may amend the return. IRS Form 8949 is to be used for these purposes and precise instructions on how to use form 8949 are forthcoming.
A list of currently approved Opportunity Zones is available on the CDFI Fund website.