diff --git a/SOURCES/rubygem-pg-1.6.0-Use-a-connection-encoding-compatible-to-M-hre.patch b/SOURCES/rubygem-pg-1.6.0-Use-a-connection-encoding-compatible-to-M-hre.patch
new file mode 100644
index 0000000..6c602d3
--- /dev/null
+++ b/SOURCES/rubygem-pg-1.6.0-Use-a-connection-encoding-compatible-to-M-hre.patch
@@ -0,0 +1,31 @@
+From dd138ecf313274cc6a5481071bf301dc8c5139d8 Mon Sep 17 00:00:00 2001
+From: Lars Kanis <lars.kanis@sincnovation.com>
+Date: Fri, 28 Feb 2025 10:39:07 +0100
+Subject: [PATCH] =?UTF-8?q?Use=20a=20connection=20encoding=20compatible=20?=
+ =?UTF-8?q?to=20"M=C3=B6hre"?=
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+The function PQescapeString was changed in PostgreSQL 17.4, 16.8, 15.12, 14.17, and 13.20.
+It now returns a predefined invalid character as a replacement in the connection encoding, if the input text is not valid according to the current connection encoding.
+Using a compatible connection encoding avoids this, so that we get the original text out of the singleton escape function.
+
+Fixes #628
+---
+ spec/pg/connection_spec.rb | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/spec/pg/connection_spec.rb b/spec/pg/connection_spec.rb
+index 63d3585..b646044 100644
+--- a/spec/pg/connection_spec.rb
++++ b/spec/pg/connection_spec.rb
+@@ -2183,7 +2183,7 @@ describe PG::Connection do
+ 
+ 			it "uses the previous string encoding for escaped string" do
+ 				original = "Möhre to 'scape".encode( "iso-8859-1" )
+-				@conn.set_client_encoding( "euc_jp" )
++				@conn.set_client_encoding( "iso-8859-2" )
+ 				escaped  = described_class.escape( original )
+ 				expect( escaped.encoding ).to eq( Encoding::ISO8859_1 )
+ 				expect( escaped ).to eq( "Möhre to ''scape".encode(Encoding::ISO8859_1) )
diff --git a/SPECS/rubygem-pg.spec b/SPECS/rubygem-pg.spec
index 0e4e1c9..1b84dd9 100644
--- a/SPECS/rubygem-pg.spec
+++ b/SPECS/rubygem-pg.spec
@@ -3,7 +3,7 @@
 
 Name: rubygem-%{gem_name}
 Version: 1.5.4
-Release: 1%{?dist}
+Release: 2%{?dist}
 Summary: A Ruby interface to the PostgreSQL RDBMS
 License: (BSD-2-Clause OR Ruby) AND PostgreSQL
 URL: https://github.com/ged/ruby-pg
@@ -27,6 +27,10 @@ Patch1: rubygem-pg-1.5.4-Explicitly-retype-timespec-fields-to-int64_t.patch
 # https://github.com/ged/ruby-pg/issues/545
 # https://github.com/ged/ruby-pg/pull/548
 Patch2: rubygem-pg-1.5.4-Fix-possible-buffer-overflows-on-32-bit-systems.patch
+# Use a compatible connection encoding in spec.
+# https://github.com/ged/ruby-pg/issues/628
+# https://github.com/ged/ruby-pg/commit/dd138ecf313274cc6a5481071bf301dc8c5139d8
+Patch3: rubygem-pg-1.6.0-Use-a-connection-encoding-compatible-to-M-hre.patch
 # ext/pg_text_decoder.c
 Requires: rubygem(bigdecimal)
 # lib/pg/text_{de,en}coder.rb
@@ -62,6 +66,10 @@ Documentation for %{name}.
 %patch -P 1 -p1
 %patch -P 2 -p1
 
+pushd %{_builddir}
+%patch 3 -p1
+popd
+
 %build
 # Create the gem as gem install only works on a gem file
 gem build ../%{gem_name}-%{version}.gemspec
@@ -133,6 +141,10 @@ popd
 %exclude %{gem_instdir}/translation
 
 %changelog
+* Tue Mar 24 2026 Jarek Prokop <jprokop@redhat.com> -1.5.4-2
+- Fix encoding issue in spec suite.
+  Resolves: RHEL-159200
+
 * Fri Jan 19 2024 Jarek Prokop <jprokop@redhat.com> - 1.5.4-1
 - Upgrade to pg 1.5.4.
   Related: RHEL-17089