diff --git a/SOURCES/mbsubstitution.patch b/SOURCES/mbsubstitution.patch
new file mode 100644
index 0000000..17e73e6
--- /dev/null
+++ b/SOURCES/mbsubstitution.patch
@@ -0,0 +1,96 @@
+--- a/sed/execute.c	2015-12-28 07:36:47.000000000 +0100
++++ b/sed/execute.c	2019-07-30 10:37:49.369052072 +0200
+@@ -213,58 +220,42 @@
+   while (length)
+     {
+       wchar_t wc;
+-      size_t n = MBRTOWC (&wc, string, length, &from_stat);
++      int n = MBRTOWC (&wc, string, length, &from_stat);
+ 
+-      /* Treat an invalid sequence like a single-byte character.  */
+-      if (n == (size_t) -1)
++      /* An invalid sequence is treated like a singlebyte character. */
++      if (n == -1)
+         {
+-          type &= ~(REPL_LOWERCASE_FIRST | REPL_UPPERCASE_FIRST);
+-          if (type == REPL_ASIS)
+-            {
+-              str_append(to, string, length);
+-              return;
+-            }
+-
+-          str_append (to, string, 1);
+           memset (&to->mbstate, 0, sizeof (from_stat));
+           n = 1;
+-          string += n, length -= n;
+-          continue;
+-        }
+-
+-      if (n == 0 || n == (size_t) -2)
+-        {
+-          /* L'\0' or an incomplete sequence: copy it manually.  */
+-          str_append(to, string, length);
+-          return;
+         }
+ 
+-      string += n, length -= n;
++      if (n > 0)
++        string += n, length -= n;
++      else
++	{
++	  /* Incomplete sequence, copy it manually.  */
++	  str_append(to, string, length);
++	  return;
++	}
+ 
+       /* Convert the first character specially... */
+       if (type & (REPL_UPPERCASE_FIRST | REPL_LOWERCASE_FIRST))
+-        {
++	{
+           if (type & REPL_UPPERCASE_FIRST)
+             wc = towupper(wc);
+           else
+             wc = towlower(wc);
+ 
+           type &= ~(REPL_LOWERCASE_FIRST | REPL_UPPERCASE_FIRST);
+-          if (type == REPL_ASIS)
+-            {
+-              /* Copy the new wide character to the end of the string. */
+-              n = WCRTOMB (to->active + to->length, wc, &to->mbstate);
+-              to->length += n;
+-              if (n == (size_t) -1 || n == (size_t) -2)
+-                {
+-                  fprintf (stderr,
+-                           _("case conversion produced an invalid character"));
+-                  abort ();
+-                }
+-              str_append(to, string, length);
+-              return;
+-            }
++	  if (type == REPL_ASIS)
++	    {
++	      n = WCRTOMB (to->active + to->length, wc, &to->mbstate);
++	      to->length += n;
++	      str_append(to, string, length);
++	      return;
++	    }
+         }
++
+       else if (type & REPL_UPPERCASE)
+         wc = towupper(wc);
+       else
+@@ -274,10 +265,10 @@
+       n = WCRTOMB (to->active + to->length, wc, &to->mbstate);
+       to->length += n;
+       if (n == -1 || n == -2)
+-        {
+-          fprintf (stderr, _("case conversion produced an invalid character"));
+-          abort ();
+-        }
++	{
++	  fprintf (stderr, "Case conversion produced an invalid character!");
++	  abort ();
++	}
+     }
+ }
+ 
diff --git a/SPECS/sed.spec b/SPECS/sed.spec
index 1db9c7c..607d937 100644
--- a/SPECS/sed.spec
+++ b/SPECS/sed.spec
@@ -6,13 +6,14 @@
 Summary: A GNU stream text editor
 Name: sed
 Version: 4.2.2
-Release: 5%{?dist}
+Release: 6%{?dist}
 License: GPLv3+
 Group: Applications/Text
 URL: http://sed.sourceforge.net/
 Source0: ftp://ftp.gnu.org/pub/gnu/sed/sed-%{version}.tar.bz2
 Source1: http://sed.sourceforge.net/sedfaq.txt
 Patch0: sed-4.2.2-binary_copy_args.patch
+Patch1: mbsubstitution.patch
 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 BuildRequires: glibc-devel, libselinux-devel
 Requires(post): /sbin/install-info
@@ -31,6 +32,7 @@ specified in a script file or from the command line.
 %prep
 %setup -q
 %patch0 -p1 -b .copy
+%patch1 -p1 -R -b .copy
 
 %build
 %configure --without-included-regex
@@ -71,6 +73,10 @@ rm -rf ${RPM_BUILD_ROOT}
 %{_mandir}/man*/*
 
 %changelog
+* Tue Jul 30 2019 Jakub Martisko <jamartis@redhat.com> - 4.2.2-6
+- Fix an issue, where some multibyte sequence substitutions were not applied 
+  Resolves: #1733877
+
 * Mon Feb 10 2014 Jan Pacner <jpacner@redhat.com> - 4.2.2-5
 - Related: #948598 (Man page scan results for sed; introduce -c argument, add
   help for -b --binary arguments, cleanup arguments & help)