For those who have reached age 70½ and beyond, ‘tis the season for receiving payments from their traditional individual retirement arrangements (IRAs), if they have not done so already. Normally, the required minimum distribution (RMD) must be taken by the end of each calendar year. However, there is a special rule allowing first time recipients, those who have reached age 70½ during 2015, a one-time extension until April 1, 2016 to receive their RMD. Although the initial RMD would be received in 2016, the second RMD would still be required by the end of 2016 and both would be taxable in 2016. Whether it is the first year or the twenty-first year, set aside some time to make sure you have received and avoid the stiff penalties that apply for failure to take your RMD.
https://www.irs.gov/uac/Newsroom/Tax-Preparedness-Series:-Most-Retirees-Need-to-Take-Required-Retirement-Plan-Distributions-by-Dec.-31