diff --git a/assertjson/assertjson.go b/assertjson/assertjson.go
index 01922f1..3b2a136 100644
--- a/assertjson/assertjson.go
+++ b/assertjson/assertjson.go
@@ -5,7 +5,7 @@ package assertjson
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"strconv"
 	"strings"
 
@@ -39,7 +39,7 @@ type JSONAssertFunc func(json *AssertJSON)
 // FileHas loads JSON from file and runs user callback for testing its nodes.
 func FileHas(t TestingT, filename string, jsonAssert JSONAssertFunc) {
 	t.Helper()
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		assert.Fail(t, fmt.Sprintf(`failed to read file "%s": %s`, filename, err.Error()))
 	} else {
diff --git a/assertxml/assertxml.go b/assertxml/assertxml.go
index c81c742..14aad1d 100644
--- a/assertxml/assertxml.go
+++ b/assertxml/assertxml.go
@@ -30,7 +30,7 @@ package assertxml
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 
 	"github.com/stretchr/testify/assert"
 	"gopkg.in/xmlpath.v2"
@@ -56,7 +56,7 @@ type XMLAssertFunc func(xml *AssertXML)
 // FileHas loads XML from file and runs user callback for testing its nodes.
 func FileHas(t TestingT, filename string, xmlAssert XMLAssertFunc) {
 	t.Helper()
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		assert.Failf(t, "failed to read file '%s': %s", filename, err.Error())
 	} else {
diff --git a/go.mod b/go.mod
index c6ca883..202c444 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/muonsoft/api-testing
 
-go 1.13
+go 1.16
 
 require (
 	github.com/gofrs/uuid v4.4.0+incompatible