Yes, the Solo 401k works just like any other retirement plan and so Required Minimum Distributions (RMDs) are mandatory. As a general rule, RMDs are first taken on April 1st of the first calendar year after the plan participant (you) turns 70.5 years old.
If you turn 70 on January 17th, 2019 you would turn 70.5 (your half birthday) on July 17th, 2019. Your first RMD would be taken on April 1st, 2020.
If you turn 70 on July 17th, 2019, you would turn 70.5 (your half birthday) on January 17th, 2020. Your first RMD would be taken on April 1st, 2021.
RMDs must be taken by December 31st for all following years, including the year you received the first RMD by April 1st. This means your first year of taking Required Minimum Distributions may have two payments; the first payment received on April 1st and the second by December 31st of that same year.
It’s really important that you take your RMD payment from your Solo 401k plan. Failure to receive an RMD (or receiving too little of a payment) can result in a 50% excise tax on the amount you were supposed to distribute.
For more information, check out the IRS website resources. Further questions should be directed to your tax advisor and/or CPA.