diff --git a/build-infer.sh b/build-infer.sh
index 4a0e7f90c..e84aa9e61 100755
--- a/build-infer.sh
+++ b/build-infer.sh
@@ -17,7 +17,7 @@ DEPENDENCIES_DIR="$INFER_ROOT/facebook/dependencies"
 PLATFORM="$(uname)"
 SANDCASTLE=${SANDCASTLE:-}
 NCPU="$(getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1)"
-INFER_OPAM_DEFAULT_SWITCH="ocaml-variants.4.08.1+flambda"
+INFER_OPAM_DEFAULT_SWITCH="ocaml-variants.4.09.1+flambda"
 INFER_OPAM_DEFAULT_COMPILER="$INFER_OPAM_DEFAULT_SWITCH"
 INFER_OPAM_SWITCH=${INFER_OPAM_SWITCH:-$INFER_OPAM_DEFAULT_SWITCH}
 INFER_OPAM_COMPILER=${INFER_OPAM_COMPILER:-$INFER_OPAM_DEFAULT_COMPILER}
diff --git a/opam b/opam
index 9703530fc..95637f144 100644
--- a/opam
+++ b/opam
@@ -34,7 +34,7 @@ depends: [
   "javalib" {>="3.2.1"}
   "mlgmpidl" {>="1.2.12"}
   "mtime"
-  "ocaml" {>="4.08.0"}
+  "ocaml" {>="4.09.0"}
   "ocamlfind" {build}
   "ocamlgraph"
   "ounit" {>="2.0.5"}
diff --git a/opam.locked b/opam.locked
index 89d80351c..219052c5c 100644
--- a/opam.locked
+++ b/opam.locked
@@ -25,15 +25,15 @@ depends: [
   "async_kernel" {= "v0.13.0"}
   "async_rpc_kernel" {= "v0.13.0"}
   "async_unix" {= "v0.13.0"}
-  "atd" {= "2.0.0"}
-  "atdgen" {= "2.0.0"}
-  "atdgen-runtime" {= "2.0.0"}
-  "base" {= "v0.13.0"}
+  "atd" {= "2.2.1"}
+  "atdgen" {= "2.2.1"}
+  "atdgen-runtime" {= "2.2.1"}
+  "base" {= "v0.13.2"}
   "base-bigarray" {= "base"}
   "base-bytes" {= "base"}
   "base-threads" {= "base"}
   "base-unix" {= "base"}
-  "base64" {= "3.3.0"}
+  "base64" {= "3.4.0"}
   "base_bigstring" {= "v0.13.0"}
   "base_quickcheck" {= "v0.13.0"}
   "bin_prot" {= "v0.13.0"}
@@ -46,24 +46,23 @@ depends: [
   "conf-m4" {= "1"}
   "conf-mpfr" {= "1"}
   "conf-perl" {= "1"}
-  "conf-pkg-config" {= "1.1"}
+  "conf-pkg-config" {= "1.2"}
   "conf-sqlite3" {= "1"}
   "conf-which" {= "1"}
   "conf-zlib" {= "1"}
   "core" {= "v0.13.0"}
-  "core_kernel" {= "v0.13.0"}
+  "core_kernel" {= "v0.13.1"}
   "cppo" {= "1.6.6"}
-  "ctypes" {= "0.16.0"}
-  "dune" {= "2.5.0"}
-  "dune-configurator" {= "2.3.1"}
-  "dune-private-libs" {= "2.3.1"}
+  "ctypes" {= "0.17.1"}
+  "dune" {= "2.5.1"}
+  "dune-configurator" {= "2.5.1"}
+  "dune-private-libs" {= "2.5.1"}
   "easy-format" {= "1.3.2"}
-  "extlib" {= "1.7.6"}
+  "extlib" {= "1.7.7"}
   "fieldslib" {= "v0.13.0"}
-  "integers" {= "0.3.0"}
+  "integers" {= "0.4.0"}
   "jane-street-headers" {= "v0.13.0"}
   "javalib" {= "3.2.1"}
-  "jbuilder" {= "1.0+beta20.2"}
   "jst-config" {= "v0.13.0"}
   "menhir" {= "20200211"}
   "menhirLib" {= "20200211"}
@@ -71,10 +70,11 @@ depends: [
   "mlgmpidl" {= "1.2.12"}
   "mtime" {= "1.2.0"}
   "num" {= "1.3"}
-  "ocaml" {= "4.08.1"}
+  "ocaml" {= "4.09.1"}
   "ocaml-compiler-libs" {= "v0.12.1"}
-  "ocaml-migrate-parsetree" {= "1.6.0"}
-  "ocaml-variants" {= "4.08.1+flambda"}
+  "ocaml-config" {= "1"}
+  "ocaml-migrate-parsetree" {= "1.7.3"}
+  "ocaml-variants" {= "4.09.1+flambda"}
   "ocamlbuild" {= "0.14.0"}
   "ocamlfind" {= "1.8.1"}
   "ocamlgraph" {= "1.8.8"}
@@ -91,14 +91,14 @@ depends: [
   "ppx_compare" {= "v0.13.0"}
   "ppx_custom_printf" {= "v0.13.0"}
   "ppx_derivers" {= "1.2.1"}
-  "ppx_deriving" {= "4.4"}
+  "ppx_deriving" {= "4.4.1"}
   "ppx_enumerate" {= "v0.13.0"}
-  "ppx_expect" {= "v0.13.0"}
+  "ppx_expect" {= "v0.13.1"}
   "ppx_fail" {= "v0.13.0"}
   "ppx_fields_conv" {= "v0.13.0"}
   "ppx_hash" {= "v0.13.0"}
   "ppx_here" {= "v0.13.0"}
-  "ppx_inline_test" {= "v0.13.0"}
+  "ppx_inline_test" {= "v0.13.1"}
   "ppx_jane" {= "v0.13.0"}
   "ppx_js_style" {= "v0.13.0"}
   "ppx_let" {= "v0.13.0"}
@@ -114,10 +114,10 @@ depends: [
   "ppx_typerep_conv" {= "v0.13.0"}
   "ppx_variants_conv" {= "v0.13.0"}
   "ppxfind" {= "1.4"}
-  "ppxlib" {= "0.12.0"}
+  "ppxlib" {= "0.13.0"}
   "protocol_version_header" {= "v0.13.0"}
   "re" {= "1.9.0"}
-  "result" {= "1.4"}
+  "result" {= "1.5"}
   "sawja" {= "1.5.8"}
   "seq" {= "base"}
   "sexplib" {= "v0.13.0"}