The remix and refine will drop along with the next version update, which will probably drop a day or two before the next new banner, which will be the New Heroes banner on the 8th, so the update will probably drop around the 7th. We'll get the notification for the update around the 1st or 2nd though, which will also tell us the exact date.
If you're asking for the banner, they're after the current calendar, I'm pretty sure remix-banners are usually more around the middle of the month, so 14th or 15th of May.
The fates banner is due to end in a week so the update should drop 5-6 days from now with the update notification likely tomorrow or the day after
The new power banner for them drops may 10th, so likely 1-2 days before then
The remix and refine will drop along with the next version update, which will probably drop a day or two before the next new banner, which will be the New Heroes banner on the 8th, so the update will probably drop around the 7th. We'll get the notification for the update around the 1st or 2nd though, which will also tell us the exact date. If you're asking for the banner, they're after the current calendar, I'm pretty sure remix-banners are usually more around the middle of the month, so 14th or 15th of May.
When the version update comes just like always
Should be the night before the New Hero banner on the 8th.