D 2.100.0 removed support for D1 operator overloads. If you have a bunch of code that still uses them, and don't want to spend the time to upgrade to D2 overloads, you can still do it, using a mixin.
Here's how it works (and shows off some cool metaprogramming features of D): https://www.schveiguy.com/blog/2022/06/how-to-keep-using-d1-operator-overloads/
-Steve