diff --git a/Sources/NIOTransportServices/NIOTSConnectionBootstrap.swift b/Sources/NIOTransportServices/NIOTSConnectionBootstrap.swift
index 93d2a83..9704289 100644
--- a/Sources/NIOTransportServices/NIOTSConnectionBootstrap.swift
+++ b/Sources/NIOTransportServices/NIOTSConnectionBootstrap.swift
@@ -263,6 +263,7 @@ public final class NIOTSConnectionBootstrap {
 
 #if swift(>=5.6)
 @available(*, unavailable)
+@available(OSX 10.14, iOS 12.0, tvOS 12.0, watchOS 6.0, *)
 extension NIOTSConnectionBootstrap: Sendable {}
 #endif