diff --git a/configure.ac b/configure.ac
index 883b25f1f..3eb02a88e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -54,6 +54,15 @@ AC_ASSERT_OCAML_PKG([easy-format])
 AC_ASSERT_OCAML_PKG([ptrees])
 AC_ASSERT_OCAML_PKG([yojson])
 
+OCAMLVERSION_MAJOR=$(printf $OCAMLVERSION | cut -d . -f 1)
+OCAMLVERSION_MINOR=$(printf $OCAMLVERSION | cut -d . -f 2)
+
+OCAML_PKG_bytes=no
+# need the bytes package for OCaml version < 4.02.0
+if test "$OCAMLVERSION_MAJOR" -le 4 && test "$OCAMLVERSION_MINOR" -lt 2; then
+AC_ASSERT_OCAML_PKG([bytes])
+fi
+
 AC_CHECK_TOOL([ATDGEN], [atdgen], [no])
 AC_ASSERT_PROG([atdgen], [$ATDGEN])
 AC_SUBST([ATDGEN])
diff --git a/infer/src/Makefile.in b/infer/src/Makefile.in
index 55075af85..206729917 100644
--- a/infer/src/Makefile.in
+++ b/infer/src/Makefile.in
@@ -42,6 +42,13 @@ EASYFORMAT_INCLUDE_DIR = @OCAML_PKG_PATH_easy_format@
 OCAML_INCLUDES = -I,$(EASYFORMAT_INCLUDE_DIR),-I,$(BINIOU_INCLUDE_DIR),-I,$(YOJSON_INCLUDE_DIR),-I,$(ATDGEN_INCLUDE_DIR)
 OCAML_LIBS = unix str atdgen
 OCAML_MODS = easy_format bi_util bi_share bi_outbuf bi_inbuf bi_vint bi_io yojson ag_oj_run ag_ob_run ag_util
+
+# backwards compatibility with OCaml version < 4.02.0
+ifneq (@OCAML_PKG_bytes@,no)
+BYTES_INCLUDE_DIR = @OCAML_PKG_PATH_bytes@
+OCAML_INCLUDES := $(OCAML_INCLUDES),-I,$(BYTES_INCLUDE_DIR)
+endif
+
 OCAMLBUILD_OPTIONS = -lflags -annot \
                      -cflags -annot,-bin-annot,-warn-error,@5@8@10..12@20@26@39 \
                      -lflags $(OCAML_INCLUDES) \
diff --git a/infer/src/backend/DB.ml b/infer/src/backend/DB.ml
index 3bb5eb59e..7d77cc42b 100644
--- a/infer/src/backend/DB.ml
+++ b/infer/src/backend/DB.ml
@@ -206,7 +206,7 @@ let create_dir dir =
 let read_whole_file fd =
   let stats = Unix.fstat fd in
   let size = stats.Unix.st_size in
-  let buf = String.create size in
+  let buf = Bytes.create size in
   let nread = Unix.read fd buf 0 size in
   if nread != size then
     begin
diff --git a/infer/src/backend/dotty.ml b/infer/src/backend/dotty.ml
index d6b5d3c63..e4f9ade22 100644
--- a/infer/src/backend/dotty.ml
+++ b/infer/src/backend/dotty.ml
@@ -112,7 +112,7 @@ let strip_special_chars s =
     if String.contains st c then begin
       let idx = String.index st c in
       try
-        String.set st idx c';
+        Bytes.set st idx c';
         st
       with Invalid_argument _ -> L.out "@\n@\n Invalid argument!!! @\n @.@.@."; assert false
     end else st in
diff --git a/infer/src/checkers/models.ml b/infer/src/checkers/models.ml
index 366bb5126..b1000ae87 100644
--- a/infer/src/checkers/models.ml
+++ b/infer/src/checkers/models.ml
@@ -49,7 +49,7 @@ module Inference = struct
 
   let update_boolvec_str _s size index bval =
     let s = if _s = "" then String.make size '0' else _s in
-    String.set s index (if bval then '1' else '0');
+    Bytes.set s index (if bval then '1' else '0');
     s
 
   let mark_file update_str dir fname =