diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -82,11 +82,9 @@
 
 ### Developing
 
-`nix-integration-test/integration-test.nix` contains a integration test, which
+`nix-integration-test/` contains a integration test, which
 uses nixos qemu vm tests to start a qemu vm with a postfix and use smtp-mail to
 send mails to that postfix.
 
-Install [nix](https://nixos.org) and execute `nix-build nix-integration-test/integration-test.nix`
-to execute the test. Success is signalled by a return code of `0`.
-
-Unconveniently it can't be run via github actions or travis, as it needs kvm virtualization.
+Install [nix](https://nixos.org), enable [flakes](https://nixos.wiki/wiki/Flakes) and execute
+`nix flake check` to execute the test. Success is signalled by a return code of `0`.
diff --git a/smtp-mail.cabal b/smtp-mail.cabal
--- a/smtp-mail.cabal
+++ b/smtp-mail.cabal
@@ -1,5 +1,5 @@
 name:                smtp-mail
-version:             0.4.0.1
+version:             0.4.0.2
 synopsis:            Simple email sending via SMTP
 description:         This packages provides a simple interface for mail over SMTP. Please see the README for more information.
 homepage:            http://github.com/haskell-github-trust/smtp-mail
@@ -42,7 +42,7 @@
                , network
                , network-bsd
                , text
-               , cryptonite
+               , crypton ^>= 1.0
                , memory
 
   ghc-options: -Wall -fwarn-tabs