Update README.md

Co-authored-by: Owen Williams <[email protected]>
Signed-off-by: Arve Knudsen <[email protected]>
diff --git a/README.md b/README.md
index 4687818..5001a34 100644
--- a/README.md
+++ b/README.md
@@ -27,4 +27,5 @@
 It's used by functions such as `model.IsValidMetricName` and `model.LabelName.IsValid`.
 _However_, if building with the _experimental_ build tag `localvalidationscheme`, the `model.NameValidationScheme` global is removed, and the API changes to accept the name validation scheme as an explicit parameter.
 `model.NameValidationScheme` is deprecated, and at some point, the API currently controlled by the build tag `localvalidationscheme` becomes standard.
+All users of this library will be expected to move to the new API, and there will be an announcement in the changelog when the global is removed.
 For the time being, the `localvalidationscheme` build tag is experimental and the API enabled by it may change.