diff --git a/README.md b/README.md
index f7b0f75..6b964a8 100644
--- a/README.md
+++ b/README.md
@@ -104,3 +104,4 @@ Otherwise `2` is the result.
 * A pure type match (without another pattern) can be written as `::Type`.
 * Types appearing in type patterns (`::Type`) and struct patterns (`Type(...)`) are bound at macro-expansion time in the context of the module containing the macro usage.  As a consequence, you cannot use certain type expressions that would differ.  For example, you cannot use a type parameter or a local variable containing a type.  The generated code checks that the type is the same at evaluation time as it was at macro expansion time, and an error is thrown if they differ.  If this rare incompatibility affects you, you can use `x where x isa Type` as a workaround.  If the type is not defined at macro-expansion time, an error is issued.
 * A warning is issued at macro-expansion time if a case cannot be reached because it is subsumed by prior cases.
+* Versions prior to `2.0.0` treated unexpected expressions as interpolations. For example, a pattern of the form `a.b` would be evaluated at pattern-match time and compared to the input. Interpolations now require the `$` syntax: `$(a.b)`.