Why doesn't backdrop-filter: blur work on iphone?

Question

css

Help me to understand.
Made a menu to which I applied

background-color: fade(@white, 10%);
backdrop-filter: blur(15px);

Everything works fine on desktops.
On android devices too.
And it doesn't work on iOS. I get only a background with transparency, but the filter does not work.
At the same time, on ios it does not work either in safari or in chrome.
I try on different phones, does not work for all.