diff --git a/Makefile.builder b/Makefile.builder
index 68a35b9..6ef27b3 100644
--- a/Makefile.builder
+++ b/Makefile.builder
@@ -1,8 +1,7 @@
 MIRAGE_KERNEL_NAME = qubes_firewall.xen
-OCAML_VERSION ?= 4.10.0
+OCAML_VERSION ?= 4.14.0
 SOURCE_BUILD_DEP := firewall-build-dep
 
 firewall-build-dep:
-	opam install -y depext
-	opam depext -i -y mirage
+	opam -i -y mirage