diff --git a/.travis.yml b/.travis.yml
index fe44134..6fdb5b5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,5 +8,6 @@ env:
   matrix:
   - PACKAGE="bigstringaf" DISTRO="ubuntu-16.04" OCAML_VERSION="4.03.0"
   - PACKAGE="bigstringaf" DISTRO="ubuntu-16.04" OCAML_VERSION="4.04.2"
-  - PACKAGE="bigstringaf" DISTRO="ubuntu-16.04" OCAML_VERSION="4.05.0"
-  - PACKAGE="bigstringaf" DISTRO="ubuntu-16.04" OCAML_VERSION="4.06.0"
+  - PACKAGE="bigstringaf" DISTRO="ubuntu-16.04" OCAML_VERSION="4.05.0" DEPOPTS="mirage-xen-posix"
+  - PACKAGE="bigstringaf" DISTRO="ubuntu-16.04" OCAML_VERSION="4.06.0" DEPOPTS="ocaml-freestanding"
+  - PACKAGE="bigstringaf" DISTRO="ubuntu-16.04" OCAML_VERSION="4.06.0" DEPOPTS="ocaml-freestanding"