diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 482ee663..292c87b8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,7 +19,7 @@ jobs:
 
       - uses: actions/setup-go@v3
         with:
-          go-version: 1.17
+          go-version: 1.18
 
       - uses: actions/cache@v3
         with:
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 5acecd9d..2df14e7a 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -20,7 +20,7 @@ jobs:
 
       - uses: actions/setup-go@v3
         with:
-          go-version: 1.17
+          go-version: 1.18
 
       - name: lint
         uses: golangci/golangci-lint-action@v3
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b0a070c4..e59e9314 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -15,7 +15,7 @@ jobs:
 
       - uses: actions/setup-go@v3
         with:
-          go-version: 1.17
+          go-version: 1.18
 
       - name: Login to Docker Hub
         uses: docker/login-action@v2
diff --git a/cli/config/configure.go b/cli/config/configure.go
index 9050073e..3c01597a 100644
--- a/cli/config/configure.go
+++ b/cli/config/configure.go
@@ -4,7 +4,6 @@ package config
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -90,7 +89,7 @@ func Configure() error {
 	if err := os.MkdirAll(filepath.Dir(configPath), 0o755); err != nil {
 		return fmt.Errorf("failed to create configuration directory: %v", err)
 	}
-	if err = ioutil.WriteFile(configPath, y, 0o666); err != nil {
+	if err = os.WriteFile(configPath, y, 0o666); err != nil {
 		return fmt.Errorf("failed to write configuration file: %v", err)
 	}
 	fmt.Printf("\nCreated configuration file at %s\n", configPath)
diff --git a/cli/ctl/apply/docparse/docparse.go b/cli/ctl/apply/docparse/docparse.go
index 5c4ed1b8..1e0a56b5 100644
--- a/cli/ctl/apply/docparse/docparse.go
+++ b/cli/ctl/apply/docparse/docparse.go
@@ -5,7 +5,6 @@ import (
 	"bufio"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"regexp"
 	"strings"
@@ -27,7 +26,7 @@ var (
 
 // FromFile parses a file to a slice of separated documents.
 func FromFile(filepath string, format Format) ([]string, error) {
-	b, err := ioutil.ReadFile(filepath)
+	b, err := os.ReadFile(filepath)
 	if err != nil {
 		return nil, err
 	}
diff --git a/cli/ctl/export/export_controller.go b/cli/ctl/export/export_controller.go
index 1ec0f756..23c6df72 100644
--- a/cli/ctl/export/export_controller.go
+++ b/cli/ctl/export/export_controller.go
@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -116,7 +115,7 @@ func (e *exportController) Execute(ctx context.Context) error {
 				}
 
 				log.Infof("Writing %s definition file %q", e.kind, outputPath)
-				if err = ioutil.WriteFile(outputPath, defDocBytes, 0o666); err != nil {
+				if err = os.WriteFile(outputPath, defDocBytes, 0o666); err != nil {
 					return err
 				}
 			}
diff --git a/cli/test/tutil/tutil.go b/cli/test/tutil/tutil.go
index 77574492..5f18eba5 100644
--- a/cli/test/tutil/tutil.go
+++ b/cli/test/tutil/tutil.go
@@ -2,7 +2,7 @@
 package tutil
 
 import (
-	"io/ioutil"
+	"os"
 	"strings"
 	"testing"
 )
@@ -21,7 +21,7 @@ func ErrorContains(out error, want string) bool {
 // Fixture returns the byte slice of a test fixture.
 func Fixture(t *testing.T, path string) []byte {
 	t.Helper()
-	fileBytes, err := ioutil.ReadFile(path)
+	fileBytes, err := os.ReadFile(path)
 	if err != nil {
 		t.Errorf("failed to load test fixture %q: %v", path, err)
 		t.FailNow()
diff --git a/core/client/client.go b/core/client/client.go
index 0205e9b3..e7efd912 100644
--- a/core/client/client.go
+++ b/core/client/client.go
@@ -6,7 +6,6 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"strings"
@@ -224,7 +223,7 @@ func (cl *Client) buildTLSOpt() error {
 
 	// Set CA cert.
 	if len(cl.cc.TLS.CACertPath) > 0 {
-		ca, err := ioutil.ReadFile(cl.cc.TLS.CACertPath)
+		ca, err := os.ReadFile(cl.cc.TLS.CACertPath)
 		if err != nil {
 			return fmt.Errorf("failed to read CA cert %q: %v", cl.cc.TLS.CACertPath, err)
 		}
@@ -239,12 +238,12 @@ func (cl *Client) buildTLSOpt() error {
 			return fmt.Errorf("both client and key cert paths must be provided, but only one found")
 		}
 
-		cert, err := ioutil.ReadFile(cl.cc.TLS.ClientCertPath)
+		cert, err := os.ReadFile(cl.cc.TLS.ClientCertPath)
 		if err != nil {
 			return fmt.Errorf("failed to read client cert %q: %v", cl.cc.TLS.ClientCertPath, err)
 		}
 
-		key, err := ioutil.ReadFile(cl.cc.TLS.ClientKeyPath)
+		key, err := os.ReadFile(cl.cc.TLS.ClientKeyPath)
 		if err != nil {
 			return fmt.Errorf("failed to read client key %q: %v", cl.cc.TLS.ClientKeyPath, err)
 		}
diff --git a/core/test/tutil/tutil.go b/core/test/tutil/tutil.go
index 853264f4..8cbc22ec 100644
--- a/core/test/tutil/tutil.go
+++ b/core/test/tutil/tutil.go
@@ -4,7 +4,7 @@ package tutil
 import (
 	"crypto/rand"
 	"encoding/json"
-	"io/ioutil"
+	"os"
 	"reflect"
 	"strings"
 	"testing"
@@ -29,7 +29,7 @@ func ErrorContains(out error, want string) bool {
 // Fixture returns the byte slice of a test fixture.
 func Fixture(t *testing.T, path string) []byte {
 	t.Helper()
-	fileBytes, err := ioutil.ReadFile(path)
+	fileBytes, err := os.ReadFile(path)
 	if err != nil {
 		t.Errorf("failed to load test fixture %q: %v", path, err)
 		t.FailNow()
diff --git a/go.mod b/go.mod
index ba24695b..92fa0b39 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/peter-evans/kdef
 
-go 1.17
+go 1.18
 
 require (
 	github.com/aws/aws-sdk-go v1.44.134