Hi Michael,
Welcome.
The list of AIRAC release dates are here.
On AIRAC release days we publish a few hours before 0900Z, which is the most common switchover time worldwide.
So AIRAC 2104 should release by 22 APR 21 0900Z.
We want the forum to be a welcoming place for you, where you can easily find answers to questions you may have . Please see Welcome to Navigraph.
After that if you have questions please ask.
Cheers
Ian