diff --git a/Proposals/0033-String-Encoding-Names.md b/Proposals/0033-String-Encoding-Names.md
index 7a9a73dca..e9e2197b8 100644
--- a/Proposals/0033-String-Encoding-Names.md
+++ b/Proposals/0033-String-Encoding-Names.md
@@ -159,9 +159,11 @@ We introduce a computed property that returns the name, and the initializer that
 ```swift
 extension String.Encoding {
   /// The name of this encoding that is compatible with the one of the IANA registry "charset".
+  @available(FoundationPreview 6.3, *)
   public var ianaName: String?
 
   /// Creates an instance from the name of the IANA registry "charset".
+  @available(FoundationPreview 6.3, *)
   public init?(ianaName: String)
 }
 ```
@@ -222,7 +224,7 @@ Accordingly, this proposal suggests just simple correspondence between `String.E
 
 ### Name to `String.Encoding`
 
-- `init(ianaName:)` adopts case-insensitive comparison with *Preferred MIME Name*, *Name*, and *Aliases*.
+- `init(ianaName:)` adopts ASCII case-insensitive comparison with *Preferred MIME Name*, *Name*, and *Aliases*.
 
 
 ## Source compatibility
@@ -232,7 +234,7 @@ These changes proposed here are only additive. However, care must be taken if mi
 
 ## Implications on adoption
 
-This feature can be freely adopted and un-adopted in source code with no deployment constraints and without affecting source compatibility.
+This feature can be freely adopted and un-adopted in source code without affecting source compatibility.
 
 
 ## Future directions