diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright Author name here (c) 2020
+Copyright Alexander Thiemann (c) 2020-2021
 
 All rights reserved.
 
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -26,6 +26,8 @@
 main =
   do manager <- newManager tlsManagerSettings
      apiKey <- T.pack <$> getEnv "STRIPE_KEY"
+     -- create a stripe client that automatically retries up to 4 times on network
+     -- errors
      let client = makeStripeClient apiKey manager 4
      result <-
          createCustomer cli (CustomerCreate Nothing (Just "mail@athiemann.net"))
@@ -36,9 +38,10 @@
 
 The package provides a module for webhook signature verification (see `Stripe.Webhook.Verify`).
 
-The implementation retries automatically according to [Stripe's error handling documentation](https://stripe.com/docs/error-handling#safely-retrying-requests-with-idempotency Stripe Error Handling).
+The implementation retries automatically according to [Stripe's error handling documentation](https://stripe.com/docs/error-handling#safely-retrying-requests-with-idempotency).
 
-Supported APIs/Resources:
+### Supported APIs/Resources:
+
 * Customers
 * Products
 * Prices
diff --git a/stripe-hs.cabal b/stripe-hs.cabal
--- a/stripe-hs.cabal
+++ b/stripe-hs.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 4019c187792644a71d436254a7f82084129aa53d02bd6af7b098b805c7ce4a38
+-- hash: bb6b65eca318fa7ead03a4c4e4713e1fb81011a04cca34f2acced717332b2c9d
 
 name:           stripe-hs
-version:        0.2.1.0
+version:        0.3.0.0
 synopsis:       Unofficial Stripe client
 description:    Unofficial Stripe client
 category:       Web
@@ -15,7 +15,7 @@
 bug-reports:    https://github.com/agrafix/stripe-hs/issues
 author:         Alexander Thiemann <mail@thiemann.at>
 maintainer:     Alexander Thiemann <mail@thiemann.at>
-copyright:      2020 Alexander Thiemann <mail@thiemann.at>
+copyright:      2020-2021 Alexander Thiemann <mail@thiemann.at>
 license:        BSD3
 license-file:   LICENSE
 build-type:     Simple
diff --git a/test/ApiSpec.hs b/test/ApiSpec.hs
--- a/test/ApiSpec.hs
+++ b/test/ApiSpec.hs
@@ -153,12 +153,14 @@
                  , cscSuccessUrl = "https://athiemann.net/success"
                  , cscClientReferenceId = Just "cool"
                  , cscCustomer = Just (cId (swCustomer sw))
+                 , cscAllowPromotionCodes = Just True
                  , cscLineItems = [CheckoutSessionCreateLineItem (pId (swPrice sw)) 1]
                  }
                csClientReferenceId session `shouldBe` Just "cool"
                csCancelUrl session `shouldBe` "https://athiemann.net/cancel"
                csSuccessUrl session `shouldBe` "https://athiemann.net/success"
                csPaymentMethodTypes session `shouldBe` V.singleton "card"
+               csAllowPromotionCodes session `shouldBe` Just True
 
                sessionRetrieved <-
                  forceSuccess $