diff --git a/fuzz_test.go b/fuzz_test.go
index 83721a39..fdf0435d 100644
--- a/fuzz_test.go
+++ b/fuzz_test.go
@@ -1,6 +1,3 @@
-//go:build go1.18 || go1.19 || go1.20 || go1.21 || go1.22
-// +build go1.18 go1.19 go1.20 go1.21 go1.22
-
 package toml_test
 
 import (
diff --git a/go.mod b/go.mod
index 35192abf..88b61fa7 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,11 @@
 module github.com/pelletier/go-toml/v2
 
-go 1.16
+go 1.21
 
 require github.com/stretchr/testify v1.9.0
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
diff --git a/go.sum b/go.sum
index 8f0c6a14..60ce688a 100644
--- a/go.sum
+++ b/go.sum
@@ -1,19 +1,10 @@
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 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/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/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
-github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
-github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
-github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 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 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 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/marshaler.go b/marshaler.go
index 7f4e20c1..fe67eccd 100644
--- a/marshaler.go
+++ b/marshaler.go
@@ -8,7 +8,7 @@ import (
 	"io"
 	"math"
 	"reflect"
-	"sort"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -280,7 +280,7 @@ func (enc *Encoder) encode(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, e
 	}
 
 	hasTextMarshaler := v.Type().Implements(textMarshalerType)
-	if hasTextMarshaler || (v.CanAddr() && reflect.PtrTo(v.Type()).Implements(textMarshalerType)) {
+	if hasTextMarshaler || (v.CanAddr() && reflect.PointerTo(v.Type()).Implements(textMarshalerType)) {
 		if !hasTextMarshaler {
 			v = v.Addr()
 		}
@@ -668,8 +668,8 @@ func (enc *Encoder) encodeMap(b []byte, ctx encoderCtx, v reflect.Value) ([]byte
 }
 
 func sortEntriesByKey(e []entry) {
-	sort.Slice(e, func(i, j int) bool {
-		return e[i].Key < e[j].Key
+	slices.SortFunc(e, func(a, b entry) int {
+		return strings.Compare(a.Key, b.Key)
 	})
 }
 
@@ -951,7 +951,7 @@ func willConvertToTable(ctx encoderCtx, v reflect.Value) bool {
 	if !v.IsValid() {
 		return false
 	}
-	if v.Type() == timeType || v.Type().Implements(textMarshalerType) || (v.Kind() != reflect.Ptr && v.CanAddr() && reflect.PtrTo(v.Type()).Implements(textMarshalerType)) {
+	if v.Type() == timeType || v.Type().Implements(textMarshalerType) || (v.Kind() != reflect.Ptr && v.CanAddr() && reflect.PointerTo(v.Type()).Implements(textMarshalerType)) {
 		return false
 	}
 
diff --git a/ossfuzz/fuzz.go b/ossfuzz/fuzz.go
index f6941908..aae03be4 100644
--- a/ossfuzz/fuzz.go
+++ b/ossfuzz/fuzz.go
@@ -1,6 +1,3 @@
-//go:build go1.18 || go1.19 || go1.20 || go1.21 || go1.22
-// +build go1.18 go1.19 go1.20 go1.21 go1.22
-
 package ossfuzz
 
 import (
diff --git a/unmarshaler.go b/unmarshaler.go
index 98231bae..38cb008f 100644
--- a/unmarshaler.go
+++ b/unmarshaler.go
@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"reflect"
 	"strings"
@@ -117,7 +116,7 @@ func (d *Decoder) EnableUnmarshalerInterface() *Decoder {
 //	Inline Table     -> same as Table
 //	Array of Tables  -> same as Array and Table
 func (d *Decoder) Decode(v interface{}) error {
-	b, err := ioutil.ReadAll(d.r)
+	b, err := io.ReadAll(d.r)
 	if err != nil {
 		return fmt.Errorf("toml: %w", err)
 	}
@@ -1078,7 +1077,7 @@ func (d *decoder) keyFromData(keyType reflect.Type, data []byte) (reflect.Value,
 		}
 		return mk, nil
 
-	case reflect.PtrTo(keyType).Implements(textUnmarshalerType):
+	case reflect.PointerTo(keyType).Implements(textUnmarshalerType):
 		mk := reflect.New(keyType)
 		if err := mk.Interface().(encoding.TextUnmarshaler).UnmarshalText(data); err != nil {
 			return reflect.Value{}, fmt.Errorf("toml: error unmarshalling key type %s from text: %w", stringType, err)