diff --git a/flow_parser.opam b/flow_parser.opam
index e499f75a20f..0e25620aaa6 100644
--- a/flow_parser.opam
+++ b/flow_parser.opam
@@ -9,7 +9,7 @@ license: "MIT"
 
 build: ["dune" "build" "-p" name "-j" jobs]
 depends: [
-  "ocaml" {>= "5.2.0"}
+  "ocaml" {>= "4.14.0"}
   "dune" {>= "3.2"}
   "base" {>= "v0.16.3"}
   "ppxlib" {>= "0.32.1"}
diff --git a/flowtype.opam b/flowtype.opam
index 20458d492d2..11d4a5ecfa1 100644
--- a/flowtype.opam
+++ b/flowtype.opam
@@ -8,7 +8,7 @@ homepage: "https://flow.org"
 doc: "https://flow.org/en/docs/getting-started/"
 bug-reports: "https://github.com/facebook/flow/issues"
 depends: [
-  "ocaml" {>= "5.2.0"}
+  "ocaml" {>= "4.14.0"}
   "base" {>= "v0.16.3"}
   "base-unix"
   "base-bytes"
diff --git a/src/parser/parser_common.ml b/src/parser/parser_common.ml
index e651749946a..ad67acf6a81 100644
--- a/src/parser/parser_common.ml
+++ b/src/parser/parser_common.ml
@@ -519,7 +519,7 @@ let is_start_of_type_guard env =
 
 let reparse_arguments_as_match_argument env (args_loc, args) =
   let { Expression.ArgList.arguments; _ } = args in
-  if List.is_empty arguments then Parser_env.error_at env (args_loc, Parse_error.MatchEmptyArgument);
+  if Base.List.is_empty arguments then Parser_env.error_at env (args_loc, Parse_error.MatchEmptyArgument);
   let filtered_args =
     List.filter_map
       (function
diff --git a/src/third-party/sedlex-ppx/ppx_sedlex.ml b/src/third-party/sedlex-ppx/ppx_sedlex.ml
index 44c063e7fe9..80f0db4bfcb 100644
--- a/src/third-party/sedlex-ppx/ppx_sedlex.ml
+++ b/src/third-party/sedlex-ppx/ppx_sedlex.ml
@@ -4,6 +4,7 @@
 
 open Ppxlib
 open Ast_builder.Default
+open Ast_helper
 
 (* let ocaml_version = Versions.ocaml_408 *)
 
@@ -359,7 +360,14 @@ let gen_state lexbuf auto i (trans, final) =
       (appfun (partition_name partition) [[%expr Sedlexing.__private__next_int [%e evar ~loc lexbuf]]])
       (cases @ [case ~lhs:[%pat? _] ~guard:None ~rhs:[%expr Sedlexing.backtrack [%e evar ~loc lexbuf]]])
   in
-  let ret body = [ value_binding ~loc ~pat:(pvar ~loc (state_fun i)) ~expr:(pexp_function ~loc [case ~lhs:(pvar ~loc lexbuf) ~guard:None ~rhs:body]) ] in
+  let ret body =
+    let lhs = pvar ~loc lexbuf in
+    [
+      value_binding ~loc
+        ~pat:(pvar ~loc (state_fun i))
+        ~expr:(Exp.fun_ ~loc Nolabel None lhs body);
+    ]
+  in
   match best_final final with
     | None -> ret (body ())
     | Some _ when Array.length trans = 0 -> []
diff --git a/tests/long_directory_names/.testconfig b/tests/long_directory_names/.testconfig
deleted file mode 100644
index 9bfaf8ba1d7..00000000000
--- a/tests/long_directory_names/.testconfig
+++ /dev/null
@@ -1,2 +0,0 @@
-auto_start: false
-shell: test.sh
diff --git a/tests/long_directory_names/long_directory_names.exp b/tests/long_directory_names/long_directory_names.exp
deleted file mode 100644
index 50a1adcd5ca..00000000000
--- a/tests/long_directory_names/long_directory_names.exp
+++ /dev/null
@@ -1,36 +0,0 @@
-
-Flow check:
-Error ------------------------------------------------------------------------------------------------------ foo.js:3:17
-
-Cannot assign `123` to `x` because number [1] is incompatible with string [2]. [incompatible-type]
-
-   foo.js:3:17
-   3| let x: string = 123
-                      ^^^ [1]
-
-References:
-   foo.js:3:8
-   3| let x: string = 123
-             ^^^^^^ [2]
-
-
-
-Found 1 error
-
-Flow status:
-Error ------------------------------------------------------------------------------------------------------ foo.js:3:17
-
-Cannot assign `123` to `x` because number [1] is incompatible with string [2]. [incompatible-type]
-
-   foo.js:3:17
-   3| let x: string = 123
-                      ^^^ [1]
-
-References:
-   foo.js:3:8
-   3| let x: string = 123
-             ^^^^^^ [2]
-
-
-
-Found 1 error
diff --git a/tests/long_directory_names/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/.flowconfig b/tests/long_directory_names/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/.flowconfig
deleted file mode 100644
index a46021e83c3..00000000000
--- a/tests/long_directory_names/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/.flowconfig
+++ /dev/null
@@ -1,13 +0,0 @@
-[ignore]
-
-[include]
-
-[libs]
-
-[lints]
-
-[options]
-all=true
-exact_by_default=false
-
-[strict]
diff --git a/tests/long_directory_names/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/foo.js b/tests/long_directory_names/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/foo.js
deleted file mode 100644
index 439a3707014..00000000000
--- a/tests/long_directory_names/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/really_long_path/foo.js
+++ /dev/null
@@ -1,3 +0,0 @@
-// @flow
-
-let x: string = 123
diff --git a/tests/long_directory_names/test.sh b/tests/long_directory_names/test.sh
deleted file mode 100644
index 926def6ca87..00000000000
--- a/tests/long_directory_names/test.sh
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/bin/bash
-# Copyright (c) Meta Platforms, Inc. and affiliates.
-#
-# This source code is licensed under the MIT license found in the
-# LICENSE file in the root directory of this source tree.
-
-# Hopefully this will be short enough not to upset windows CI
-LONG_PATH="really_long_path/really_long_path/really_long_path/really_long_path/\
-really_long_path/really_long_path/really_long_path/really_long_path/\
-really_long_path/really_long_path/really_long_path"
-
-printf "\nFlow check:\n"
-assert_errors "$FLOW" check --strip-root "$LONG_PATH"
-
-printf "\nFlow status:\n"
-start_flow "$LONG_PATH"
-assert_errors "$FLOW" status --strip-root --no-auto-start "$LONG_PATH"
-assert_ok "$FLOW" stop "$LONG_PATH"