diff -Nru ocaml-num-1.3/Changelog ocaml-num-1.4/Changelog
--- ocaml-num-1.3/Changelog	2019-11-20 08:24:08.000000000 +0000
+++ ocaml-num-1.4/Changelog	2020-11-09 16:22:09.000000000 +0000
@@ -1,3 +1,8 @@
+Release 1.4 (2020-11-09)
+
+- Pull request #20: fix bug caused by unsafe string/bytes conversions,
+  and remove all uses of `Bytes.unsafe_of_string`
+
 Release 1.3 (2019-11-20)
 
 - Pull request #16: use Sys.word_size and Sys.int_size more consistently
diff -Nru ocaml-num-1.3/debian/changelog ocaml-num-1.4/debian/changelog
--- ocaml-num-1.3/debian/changelog	2020-11-02 13:08:58.000000000 +0000
+++ ocaml-num-1.4/debian/changelog	2020-11-24 09:35:39.000000000 +0000
@@ -1,8 +1,10 @@
-ocaml-num (1.3-1build1) hirsute; urgency=medium
+ocaml-num (1.4-1) unstable; urgency=medium
 
-  * No-change rebuild for ocaml abi changes.
+  * New upstream release
+  * Bump debhelper compat level to 13
+  * Bump Standards-Version to 4.5.1
 
- -- Matthias Klose <doko@ubuntu.com>  Mon, 02 Nov 2020 14:08:58 +0100
+ -- Stéphane Glondu <glondu@debian.org>  Tue, 24 Nov 2020 10:35:39 +0100
 
 ocaml-num (1.3-1) unstable; urgency=medium
 
diff -Nru ocaml-num-1.3/debian/control ocaml-num-1.4/debian/control
--- ocaml-num-1.3/debian/control	2019-12-02 10:29:25.000000000 +0000
+++ ocaml-num-1.4/debian/control	2020-11-24 09:35:39.000000000 +0000
@@ -4,12 +4,12 @@
 Uploaders:
  Stéphane Glondu <glondu@debian.org>
 Build-Depends:
- debhelper-compat (= 12),
+ debhelper-compat (= 13),
  dh-ocaml,
  ocaml-nox (>= 4.08),
  ocaml-findlib
 Rules-Requires-Root: no
-Standards-Version: 4.4.1
+Standards-Version: 4.5.1
 Section: ocaml
 Homepage: https://github.com/ocaml/num
 Vcs-Git: https://salsa.debian.org/ocaml-team/ocaml-num.git
diff -Nru ocaml-num-1.3/debian/rules ocaml-num-1.4/debian/rules
--- ocaml-num-1.3/debian/rules	2019-12-02 10:29:25.000000000 +0000
+++ ocaml-num-1.4/debian/rules	2020-11-24 09:35:39.000000000 +0000
@@ -8,8 +8,3 @@
 
 %:
 	dh $@ --with ocaml
-
-override_dh_missing:
-	dh_missing --fail-missing
-
-override_dh_dwz:
diff -Nru ocaml-num-1.3/num.opam ocaml-num-1.4/num.opam
--- ocaml-num-1.3/num.opam	2019-11-20 08:24:08.000000000 +0000
+++ ocaml-num-1.4/num.opam	2020-11-09 16:22:09.000000000 +0000
@@ -1,5 +1,5 @@
 opam-version: "2.0"
-version: "1.3"
+version: "1.4"
 maintainer: "Xavier Leroy <xavier.leroy@inria.fr>"
 authors: [
   "Valérie Ménissier-Morain"
diff -Nru ocaml-num-1.3/src/big_int.ml ocaml-num-1.4/src/big_int.ml
--- ocaml-num-1.3/src/big_int.ml	2019-11-20 08:24:08.000000000 +0000
+++ ocaml-num-1.4/src/big_int.ml	2020-11-09 16:22:09.000000000 +0000
@@ -674,7 +674,7 @@
                                       (big_int_of_string "963295986"))
                         (big_int_of_string "100000000")))) in
   let s =
-    Bytes.unsafe_of_string
+    Bytes.of_string
       (string_of_big_int (div_big_int bi (power_int_positive_int 10 n)))
   in
   let (sign, off) =
diff -Nru ocaml-num-1.3/src/ratio.ml ocaml-num-1.4/src/ratio.ml
--- ocaml-num-1.3/src/ratio.ml	2019-11-20 08:24:08.000000000 +0000
+++ ocaml-num-1.4/src/ratio.ml	2020-11-09 16:22:09.000000000 +0000
@@ -438,13 +438,13 @@
                    (base_power_big_int
                        10 (succ n) (abs_big_int r.numerator))
                    r.denominator)) in
+       let s1 = Bytes.of_string s1 in
        (* Round up and add 1 in front if needed *)
        let s2 =
-         if round_futur_last_digit (Bytes.unsafe_of_string s1) 0
-                                   (String.length s1)
-         then "1" ^ s1
+         if round_futur_last_digit s1 0 (Bytes.length s1)
+         then Bytes.cat (Bytes.of_string "1") s1
          else s1 in
-       let l2 = String.length s2 - 1 in
+       let l2 = Bytes.length s2 - 1 in
        (*   if s2 without last digit is xxxxyyy with n 'yyy' digits:
                <sign> xxxx . yyy
             if s2 without last digit is      yy with <= n digits:
@@ -452,15 +452,15 @@
        if l2 > n then begin
          let s = Bytes.make (l2 + 2) '0' in
          Bytes.set s 0  (if sign_r = -1 then '-' else '+');
-         String.blit s2 0 s 1 (l2 - n);
+         Bytes.blit s2 0 s 1 (l2 - n);
          Bytes.set s (l2 - n + 1) '.';
-         String.blit s2 (l2 - n) s (l2 - n + 2) n;
+         Bytes.blit s2 (l2 - n) s (l2 - n + 2) n;
          Bytes.unsafe_to_string s
        end else begin
          let s = Bytes.make (n + 3) '0' in
          Bytes.set s 0  (if sign_r = -1 then '-' else '+');
          Bytes.set s 2 '.';
-         String.blit s2 0 s (n + 3 - l2) l2;
+         Bytes.blit s2 0 s (n + 3 - l2) l2;
          Bytes.unsafe_to_string s
        end
      end else begin
@@ -508,8 +508,8 @@
                                 10 k (abs_big_int r.numerator))
                                r.denominator) in
        string_of_nat nat) in
-     if round_futur_last_digit (Bytes.unsafe_of_string s) 0
-                               (String.length s)
+     let s = Bytes.of_string s in
+     if round_futur_last_digit s 0 (Bytes.length s)
       then
        let m = num_decimal_digits_int (succ msd) in
        let str = Bytes.make (n + m + 4) '0' in
@@ -525,7 +525,7 @@
       and p = n + 3 in
       let str = Bytes.make (succ (m + p)) '0' in
         (String.blit (if sign_r = -1 then "-0." else "+0.") 0 str 0 3);
-        (String.blit s 0 str 3 n);
+        (Bytes.blit s 0 str 3 n);
         Bytes.set str p 'e';
         (if m = 0
           then Bytes.set str (succ p) '0'