diff --git a/Package.swift b/Package.swift
index 3951a29..37ecffd 100644
--- a/Package.swift
+++ b/Package.swift
@@ -6,9 +6,11 @@ import PackageDescription
 let package = Package(
     name: "UID2",
     defaultLocalization: "en",
+    // NB: The UID2 framework code only runs on iOS 13 & tvOS 13, however this allows
+    // integration in apps supporting iOS 12.
     platforms: [
-        .iOS(.v13),
-        .tvOS(.v13)
+        .iOS(.v12),
+        .tvOS(.v12)
     ],
     products: [
         .library(
diff --git a/Sources/UID2/CryptoUtil.swift b/Sources/UID2/CryptoUtil.swift
index 5e16329..88a6c59 100644
--- a/Sources/UID2/CryptoUtil.swift
+++ b/Sources/UID2/CryptoUtil.swift
@@ -9,6 +9,7 @@ import CryptoKit
 import Foundation
 import SwiftASN1
 
+@available(iOS 13, tvOS 13, *)
 struct CryptoUtil: Sendable {
     // Parses a server's public key and returns a newly generated public key and symmetric key.
     var parseKey: @Sendable (_ string: String) throws -> (SymmetricKey, P256.KeyAgreement.PublicKey)
@@ -17,6 +18,7 @@ struct CryptoUtil: Sendable {
     var encrypt: @Sendable (_ data: Data, _ key: SymmetricKey, _ authenticatedData: Data) throws -> AES.GCM.SealedBox
 }
 
+@available(iOS 13, tvOS 13, *)
 extension CryptoUtil {
     private static let serverPublicKeyPrefixLength = 9
 
diff --git a/Sources/UID2/Extensions/PublicKey+Extensions.swift b/Sources/UID2/Extensions/PublicKey+Extensions.swift
index e0f1e01..279608c 100644
--- a/Sources/UID2/Extensions/PublicKey+Extensions.swift
+++ b/Sources/UID2/Extensions/PublicKey+Extensions.swift
@@ -9,6 +9,7 @@ import CryptoKit
 import Foundation
 import SwiftASN1
 
+@available(iOS 13, tvOS 13, *)
 extension P256.KeyAgreement.PublicKey {
     // CryptoKit's implementation is only available in iOS 14
     var derRepresentation: Data {
diff --git a/Sources/UID2/Extensions/URLSession+Extensions.swift b/Sources/UID2/Extensions/URLSession+Extensions.swift
index e7c0b09..8dae129 100644
--- a/Sources/UID2/Extensions/URLSession+Extensions.swift
+++ b/Sources/UID2/Extensions/URLSession+Extensions.swift
@@ -7,6 +7,7 @@
 
 import Foundation
 
+@available(iOS 13, tvOS 13, *)
 extension URLSession: NetworkSession {
 
     func loadData(for request: URLRequest) async throws -> (Data, HTTPURLResponse) {
diff --git a/Sources/UID2/Internal/Broadcaster.swift b/Sources/UID2/Internal/Broadcaster.swift
index 278b38f..d403eaa 100644
--- a/Sources/UID2/Internal/Broadcaster.swift
+++ b/Sources/UID2/Internal/Broadcaster.swift
@@ -1,6 +1,7 @@
 import Foundation
 
 /// Send a value to multiple observers
+@available(iOS 13, tvOS 13, *)
 actor Broadcaster<Element: Sendable> {
     typealias Identifier = UUID
     private var continuations: [Identifier: AsyncStream<Element>.Continuation] = [:]
diff --git a/Sources/UID2/Internal/Queue.swift b/Sources/UID2/Internal/Queue.swift
index 93fc8e9..d00663a 100644
--- a/Sources/UID2/Internal/Queue.swift
+++ b/Sources/UID2/Internal/Queue.swift
@@ -3,6 +3,7 @@ import Foundation
 /// When bridging from a sync to async context using multiple `Task`s, order of execution is not guaranteed.
 /// Using an `AsyncStream` we can bridge enqueued work to an async context within a single `Task`.
 /// https://forums.swift.org/t/a-pitfall-when-using-didset-and-task-together-order-cant-be-guaranteed/71311/6
+@available(iOS 13, tvOS 13, *)
 final class Queue {
     typealias Operation = @Sendable () async -> Void
     private let continuation: AsyncStream<Operation>.Continuation
diff --git a/Sources/UID2/KeychainManager.swift b/Sources/UID2/KeychainManager.swift
index 8e9f2aa..d5f6875 100644
--- a/Sources/UID2/KeychainManager.swift
+++ b/Sources/UID2/KeychainManager.swift
@@ -5,6 +5,7 @@
 import Foundation
 import Security
 
+@available(iOS 13, tvOS 13, *)
 extension Storage {
     static func keychainStorage() -> Storage {
         let storage = KeychainManager()
@@ -17,6 +18,7 @@ extension Storage {
 }
 
 /// Securely manages data in the Keychain
+@available(iOS 13, tvOS 13, *)
 actor KeychainManager {
 
     private let attrAccount = "uid2"
diff --git a/Sources/UID2/Networking/ClientGenerate.swift b/Sources/UID2/Networking/ClientGenerate.swift
index 8b361b2..1d91cd9 100644
--- a/Sources/UID2/Networking/ClientGenerate.swift
+++ b/Sources/UID2/Networking/ClientGenerate.swift
@@ -9,6 +9,8 @@ import CryptoKit
 import Foundation
 
 extension Request {
+
+    @available(iOS 13, tvOS 13, *)
     static func clientGenerate(
         payload: Data,
         initializationVector: Data,
@@ -54,6 +56,7 @@ struct ClientGeneratePayload: Encodable {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 extension ClientGeneratePayload {
     init(_ identity: IdentityType) {
         switch identity {
@@ -87,6 +90,7 @@ struct ClientGenerateRequestBody: Encodable {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 fileprivate extension String {
     func sha256hash() -> Data {
         let digest = SHA256.hash(data: Data(self.utf8))
diff --git a/Sources/UID2/Networking/DataEnvelope.swift b/Sources/UID2/Networking/DataEnvelope.swift
index 389ce31..4f93823 100644
--- a/Sources/UID2/Networking/DataEnvelope.swift
+++ b/Sources/UID2/Networking/DataEnvelope.swift
@@ -8,6 +8,7 @@
 import CryptoKit
 import Foundation
 
+@available(iOS 13, tvOS 13, *)
 internal enum DataEnvelope {
 
     /// Decrypts raw response envelope data, which is expected to be a base64 encoded string.
diff --git a/Sources/UID2/Networking/NetworkSession.swift b/Sources/UID2/Networking/NetworkSession.swift
index 34fb6de..faeac48 100644
--- a/Sources/UID2/Networking/NetworkSession.swift
+++ b/Sources/UID2/Networking/NetworkSession.swift
@@ -8,6 +8,7 @@
 import Foundation
 
 /// Common interface for networking and unit testing
+@available(iOS 13, tvOS 13, *)
 protocol NetworkSession: Sendable {
     
     func loadData(for request: URLRequest) async throws -> (Data, HTTPURLResponse)
diff --git a/Sources/UID2/UID2Client.swift b/Sources/UID2/UID2Client.swift
index c9c899b..a3b9b8c 100644
--- a/Sources/UID2/UID2Client.swift
+++ b/Sources/UID2/UID2Client.swift
@@ -14,6 +14,7 @@ import Foundation
 #endif
 @preconcurrency import OSLog
 
+@available(iOS 13, tvOS 13, *)
 internal final class UID2Client: Sendable {
     private let clientVersion: String
     private let environment: Environment
diff --git a/Sources/UID2/UID2Manager.State.swift b/Sources/UID2/UID2Manager.State.swift
index 8bddd8f..1e2d858 100644
--- a/Sources/UID2/UID2Manager.State.swift
+++ b/Sources/UID2/UID2Manager.State.swift
@@ -4,6 +4,7 @@
 
 import Foundation
 
+@available(iOS 13, tvOS 13, *)
 extension UID2Manager {
     public enum State: Hashable, Sendable, Codable {
         case optout
@@ -15,6 +16,7 @@ extension UID2Manager {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 extension UID2Manager.State {
     /// A 'case path' returning the current `IdentityStatus`.
     public var identityStatus: IdentityStatus {
@@ -49,6 +51,7 @@ extension UID2Manager.State {
     }
 }
 
+@available(iOS 13, tvOS 13, *)
 extension UID2Manager.State {
     init?(_ package: IdentityPackage) {
         switch package.status {
diff --git a/Sources/UID2/UID2Manager.swift b/Sources/UID2/UID2Manager.swift
index d9f5dba..fc7e29f 100644
--- a/Sources/UID2/UID2Manager.swift
+++ b/Sources/UID2/UID2Manager.swift
@@ -10,6 +10,7 @@ import Foundation
 import OSLog
 
 // swiftlint:disable:next type_body_length
+@available(iOS 13, tvOS 13, *)
 public final actor UID2Manager {
     private enum InitializationState {
         case pending
diff --git a/Tests/TestHelpers/TestCryptoUtil.swift b/Tests/TestHelpers/TestCryptoUtil.swift
index de8a583..bef9c7e 100644
--- a/Tests/TestHelpers/TestCryptoUtil.swift
+++ b/Tests/TestHelpers/TestCryptoUtil.swift
@@ -36,6 +36,7 @@ private final class Atomic<Value: Sendable>: @unchecked Sendable {
 
 /// A test convenience which exposes the Symmetric Key it generates for the client.
 /// This key can then be used to encrypt stub responses for the client.
+@available(iOS 13, tvOS 13, *)
 public final class TestCryptoUtil {
     private let atomicSymmetricKey: Atomic<SymmetricKey?>
 
diff --git a/Tests/TestHelpers/XCTest+Extensions.swift b/Tests/TestHelpers/XCTest+Extensions.swift
index fc51f56..99c4ad9 100644
--- a/Tests/TestHelpers/XCTest+Extensions.swift
+++ b/Tests/TestHelpers/XCTest+Extensions.swift
@@ -8,6 +8,7 @@
 import XCTest
 
 /// `XCTAssertThrowsError` doesn't support async expressions.
+@available(iOS 13, tvOS 13, *)
 public func assertThrowsError<T>(
     _ expression: @escaping @autoclosure () async throws -> T,
     _ message: @autoclosure () -> String = "",
diff --git a/UID2.podspec.json b/UID2.podspec.json
index 7450727..91424b5 100644
--- a/UID2.podspec.json
+++ b/UID2.podspec.json
@@ -12,8 +12,8 @@
     "tag": "v1.5.0"
   },
   "platforms": {
-    "ios": "13.0",
-    "tvos": "13.0"
+    "ios": "12.0",
+    "tvos": "12.0"
   },
   "swift_versions": [
     "5"