diff --git a/.cirrus.yml b/.cirrus.yml
index 859a2ea7..283c8ed6 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -8,8 +8,9 @@ freebsd_task:
     matrix:
       - OCAML_VERSION: 4.08.1
       - OCAML_VERSION: 4.09.1
-      - OCAML_VERSION: 4.10.1
-      - OCAML_VERSION: 4.11.1
+      - OCAML_VERSION: 4.10.2
+      - OCAML_VERSION: 4.11.2
+      - OCAML_VERSION: 4.12.0
   pkg_install_script: pkg install -y ocaml-opam gmp gmake pkgconf bash
   ocaml_script: opam init -a --comp=$OCAML_VERSION
   solo5_script: eval `opam env` && opam install solo5-bindings-hvt
diff --git a/.travis.yml b/.travis.yml
index 82b51ed1..9a4d6a15 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,28 +14,34 @@ env:
 jobs:
   include:
     # Build using the latest OCaml release on most common targets and architectures.
-    - name: OCaml 4.11, Solo5/hvt (amd64)
+    - name: OCaml 4.12, Solo5/hvt (amd64)
       arch: amd64
-      env: OCAML_VERSION=4.11 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
-    - name: OCaml 4.11, Solo5/hvt, system switch (amd64)
+      env: OCAML_VERSION=4.12 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
+    - name: OCaml 4.12, Solo5/hvt (amd64)
       arch: amd64
-      env: OCAML_VERSION=4.11 INSTALL_LOCAL=1 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
-    - name: OCaml 4.11, Solo5/spt (amd64)
+      env: OCAML_VERSION=4.12 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
+    - name: OCaml 4.12, Solo5/hvt, system switch (amd64)
       arch: amd64
-      env: OCAML_VERSION=4.11 EXTRA_DEPS="solo5-bindings-spt" EXTRA_ENV="MIRAGE_TEST_MODE=spt"
-    - name: OCaml 4.11, Solo5/virtio (amd64)
+      env: OCAML_VERSION=4.12 INSTALL_LOCAL=1 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
+    - name: OCaml 4.12, Solo5/spt (amd64)
       arch: amd64
-      env: OCAML_VERSION=4.11 EXTRA_DEPS="solo5-bindings-virtio" EXTRA_ENV="MIRAGE_TEST_MODE=virtio"
-    - name: OCaml 4.11, Solo5/muen (amd64)
+      env: OCAML_VERSION=4.12 EXTRA_DEPS="solo5-bindings-spt" EXTRA_ENV="MIRAGE_TEST_MODE=spt"
+    - name: OCaml 4.12, Solo5/virtio (amd64)
       arch: amd64
-      env: OCAML_VERSION=4.11 EXTRA_DEPS="solo5-bindings-muen" EXTRA_ENV="MIRAGE_TEST_MODE=muen"
-    - name: OCaml 4.11, Solo5/hvt (arm64)
+      env: OCAML_VERSION=4.12 EXTRA_DEPS="solo5-bindings-virtio" EXTRA_ENV="MIRAGE_TEST_MODE=virtio"
+    - name: OCaml 4.12, Solo5/muen (amd64)
+      arch: amd64
+      env: OCAML_VERSION=4.12 EXTRA_DEPS="solo5-bindings-muen" EXTRA_ENV="MIRAGE_TEST_MODE=muen"
+    - name: OCaml 4.12, Solo5/hvt (arm64)
       arch: arm64
-      env: OCAML_VERSION=4.11 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
-    - name: OCaml 4.11, Solo5/spt (arm64)
+      env: OCAML_VERSION=4.12 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
+    - name: OCaml 4.12, Solo5/spt (arm64)
       arch: arm64
-      env: OCAML_VERSION=4.11 EXTRA_DEPS="solo5-bindings-spt" EXTRA_ENV="MIRAGE_TEST_MODE=spt"
+      env: OCAML_VERSION=4.12 EXTRA_DEPS="solo5-bindings-spt" EXTRA_ENV="MIRAGE_TEST_MODE=spt"
     # Build previous but still supported OCaml releases only on amd64 and hvt.
+    - name: OCaml 4.11, Solo5/hvt (amd64)
+      arch: amd64
+      env: OCAML_VERSION=4.11 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
     - name: OCaml 4.10, Solo5/hvt (amd64)
       arch: amd64
       env: OCAML_VERSION=4.10 EXTRA_DEPS="solo5-bindings-hvt" EXTRA_ENV="MIRAGE_TEST_MODE=hvt"
diff --git a/nolibc/include/sys/stat.h b/nolibc/include/sys/stat.h
index decc7255..a473df40 100644
--- a/nolibc/include/sys/stat.h
+++ b/nolibc/include/sys/stat.h
@@ -1,6 +1,8 @@
 #ifndef _SYS_STAT_H
 #define _SYS_STAT_H
 
+#include <sys/types.h>
+
 struct stat {
     int st_mode;
 };
@@ -9,5 +11,6 @@ struct stat {
 #define S_IFREG 0
 #define S_ISREG(x) (0)
 int stat(const char *, struct stat *);
+int mkdir(const char *, mode_t);
 
 #endif
diff --git a/nolibc/include/sys/types.h b/nolibc/include/sys/types.h
index 50f4a486..a916f597 100644
--- a/nolibc/include/sys/types.h
+++ b/nolibc/include/sys/types.h
@@ -7,5 +7,6 @@
 typedef int pid_t;
 typedef int off_t;
 typedef int ssize_t;
+typedef int mode_t;
 
 #endif
diff --git a/nolibc/include/unistd.h b/nolibc/include/unistd.h
index fdfa5b32..479e6fcf 100644
--- a/nolibc/include/unistd.h
+++ b/nolibc/include/unistd.h
@@ -14,5 +14,6 @@ ssize_t read(int, void *, size_t);
 ssize_t write(int, const void *, size_t);
 ssize_t readlink(const char *, char *, size_t);
 int unlink(const char *);
+int rmdir(const char *);
 
 #endif
diff --git a/nolibc/stubs.c b/nolibc/stubs.c
index a0ec78ef..5f951b0a 100644
--- a/nolibc/stubs.c
+++ b/nolibc/stubs.c
@@ -74,6 +74,7 @@ STUB_IGNORE(off_t, lseek, -1);
 STUB_ABORT(read);
 STUB_IGNORE(int, readlink, -1);
 STUB_ABORT(unlink);
+STUB_ABORT(rmdir);
 
 /* dirent.h */
 STUB_WARN_ONCE(int, closedir, -1);
@@ -98,3 +99,4 @@ STUB_ABORT(strerror);
 
 /* sys/stat.h */
 STUB_WARN_ONCE(int, stat, -1);
+STUB_ABORT(mkdir);
diff --git a/opam b/opam
index bcfaa2ad..ca63c537 100644
--- a/opam
+++ b/opam
@@ -13,7 +13,7 @@ depends: [
   "ocamlfind" {build}
   "ocaml-src" {build}
   ("solo5-bindings-hvt" | "solo5-bindings-spt" | "solo5-bindings-virtio" | "solo5-bindings-muen" | "solo5-bindings-genode" | "solo5-bindings-xen")
-  "ocaml" {>= "4.08.0" & < "4.12.0"}
+  "ocaml" {>= "4.08.0" & < "4.13.0"}
 ]
 substs: [
   "flags/cflags.tmp"