diff --git a/go.mod b/go.mod
index 1834482..048a396 100644
--- a/go.mod
+++ b/go.mod
@@ -5,11 +5,15 @@ go 1.21
 toolchain go1.23.4
 
 require (
+	github.com/stretchr/testify v1.10.0
 	go.unistack.org/micro-proto/v3 v3.4.1
 	go.unistack.org/micro/v3 v3.10.88
 )
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/google/go-cmp v0.6.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	google.golang.org/protobuf v1.35.2 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/go.sum b/go.sum
index 2eb7409..3e1c705 100644
--- a/go.sum
+++ b/go.sum
@@ -1,8 +1,18 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.unistack.org/micro-proto/v3 v3.4.1 h1:UTjLSRz2YZuaHk9iSlVqqsA50JQNAEK2ZFboGqtEa9Q=
 go.unistack.org/micro-proto/v3 v3.4.1/go.mod h1:okx/cnOhzuCX0ggl/vToatbCupi0O44diiiLLsZ93Zo=
 go.unistack.org/micro/v3 v3.10.88 h1:MxlzP+77Y6Kphb3lzHxROL4XfE/WdCQMQpnPv4D9Z8U=
 go.unistack.org/micro/v3 v3.10.88/go.mod h1:erMgt3Bl7vQQ0e9UpQyR5NlLiZ9pKeEJ9+1tfYFaqUg=
 google.golang.org/protobuf v1.35.2 h1:8Ar7bF+apOIoThw1EdZl0p1oWvMqTHmpA2fRTyZO8io=
 google.golang.org/protobuf v1.35.2/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/reader_test.go b/reader_test.go
new file mode 100644
index 0000000..2686e6a
--- /dev/null
+++ b/reader_test.go
@@ -0,0 +1,40 @@
+package xml
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestReader_Read(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    []byte
+		expected []byte
+	}{
+		{
+			name:     "with replacement",
+			input:    []byte(`<?xml version="1.1" encoding="UTF-8"?><root name="NAME"><item>ITEM</item></root>`),
+			expected: []byte(`<?xml version="1.0" encoding="UTF-8"?><root name="NAME"><item>ITEM</item></root>`),
+		},
+		{
+			name:     "without replacement",
+			input:    []byte(`<?xml version="1.0" encoding="UTF-8"?><root name="NAME"><item>ITEM</item></root>`),
+			expected: []byte(`<?xml version="1.0" encoding="UTF-8"?><root name="NAME"><item>ITEM</item></root>`),
+		},
+		{
+			name:     "check invalid replacement",
+			input:    []byte(`<?xml version="1.0" encoding="UTF-8"?><root version="1.1"><item>ITEM</item></root>`),
+			expected: []byte(`<?xml version="1.0" encoding="UTF-8"?><root version="1.1"><item>ITEM</item></root>`),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			buf := make([]byte, len(tt.input))
+			n, err := newReader(tt.input).Read(buf)
+			require.NoError(t, err)
+			require.Equal(t, tt.expected, buf[:n])
+		})
+	}
+}
diff --git a/xml.go b/xml.go
index 870933f..6c189dd 100644
--- a/xml.go
+++ b/xml.go
@@ -134,9 +134,9 @@ func newReader(b []byte) io.Reader {
 }
 
 var (
-	srcP = []byte(`version="1.1"`)
+	srcP = []byte(`<?xml version="1.1"`)
 	srcL = len(srcP)
-	dstP = []byte(`version="1.0"`)
+	dstP = []byte(`<?xml version="1.0"`)
 )
 
 func (r *reader) Read(b []byte) (n int, err error) {
@@ -146,7 +146,7 @@ func (r *reader) Read(b []byte) (n int, err error) {
 	r.prevRune = -1
 	n = copy(b, r.s[r.i:])
 	if !r.skip {
-		if idx := bytes.Index(b, srcP); idx > 0 {
+		if idx := bytes.Index(b, srcP); idx >= 0 {
 			copy(b[idx:idx+srcL], dstP)
 			r.skip = true
 		}
diff --git a/xml_test.go b/xml_test.go
new file mode 100644
index 0000000..a0872d8
--- /dev/null
+++ b/xml_test.go
@@ -0,0 +1,70 @@
+package xml
+
+import (
+	"encoding/xml"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.unistack.org/micro/v3/codec"
+)
+
+func TestXmlCodec_Unmarshal(t *testing.T) {
+	type result struct {
+		XMLName xml.Name `xml:"root"`
+		Name    string   `xml:"name,attr"`
+		Item    string   `xml:"item"`
+	}
+
+	tests := []struct {
+		name     string
+		input    []byte
+		isXML11  bool
+		expected result
+	}{
+		{
+			name:  "without version",
+			input: []byte(`<root name="NAME"><item>ITEM</item></root>`),
+			expected: result{
+				XMLName: xml.Name{Local: "root"},
+				Name:    "NAME",
+				Item:    "ITEM",
+			},
+		},
+		{
+			name:  "version 1.0",
+			input: []byte(`<?xml version="1.0" encoding="UTF-8"?><root name="NAME"><item>ITEM</item></root>`),
+			expected: result{
+				XMLName: xml.Name{Local: "root"},
+				Name:    "NAME",
+				Item:    "ITEM",
+			},
+		},
+		{
+			name:    "version 1.1",
+			input:   []byte(`<?xml version="1.1" encoding="UTF-8"?><root name="NAME"><item>ITEM</item></root>`),
+			isXML11: true,
+			expected: result{
+				XMLName: xml.Name{Local: "root"},
+				Name:    "NAME",
+				Item:    "ITEM",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var (
+				r    result
+				opts []codec.Option
+			)
+
+			if tt.isXML11 {
+				opts = append(opts, UnmarshalXML11(true))
+			}
+
+			err := NewCodec(opts...).Unmarshal(tt.input, &r)
+			require.NoError(t, err)
+			require.Equal(t, tt.expected, r)
+		})
+	}
+}