diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e00ccf0..fd3536f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,17 +14,17 @@ jobs:
 
     strategy:
       matrix:
-        go-version: [1.12.x, 1.13.x, 1.20.x]
+        go-version: [1.20.x]
         os: [ubuntu-latest, macos-latest, windows-latest]
 
     env:
       ENV: test
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
 
       - name: Install Go
-        uses: actions/setup-go@v1
+        uses: actions/setup-go@v5
         with:
           go-version: ${{matrix.go-version}}
 
diff --git a/errors.go b/errors.go
index 762f3c8..7f15c36 100644
--- a/errors.go
+++ b/errors.go
@@ -10,12 +10,13 @@ import (
 type ErrorCode string
 
 const (
-	InternalError    ErrorCode = "Internal Error"
-	NotFound         ErrorCode = "Not Found"
-	InvalidArgument  ErrorCode = "Invalid Argument"
-	Unauthenticated  ErrorCode = "Unauthenticated"
-	PermissionDenied ErrorCode = "Permission Denied"
-	Unknown          ErrorCode = "Unknown"
+	InternalError        ErrorCode = "Internal Error"
+	NotFound             ErrorCode = "Not Found"
+	InvalidArgument      ErrorCode = "Invalid Argument"
+	Unauthenticated      ErrorCode = "Unauthenticated"
+	PermissionDenied     ErrorCode = "Permission Denied"
+	UnprocessableContent ErrorCode = "Unprocessable Content"
+	Unknown              ErrorCode = "Unknown"
 )
 
 type customError struct {
@@ -30,7 +31,7 @@ func (code ErrorCode) New(msg string) error {
 }
 
 // Newf creates a new customError with formatted message
-func (code ErrorCode) Newf(msg string, args ...interface{}) error {
+func (code ErrorCode) Newf(msg string, args ...any) error {
 	return customError{code: code, originalError: fmt.Errorf(msg, args...)}
 }
 
@@ -40,7 +41,7 @@ func (code ErrorCode) Wrap(err error, msg string) error {
 }
 
 // Wrapf creates a new wrapped error with formatted message
-func (code ErrorCode) Wrapf(err error, msg string, args ...interface{}) error {
+func (code ErrorCode) Wrapf(err error, msg string, args ...any) error {
 	return customError{code: code, originalError: errors.Wrapf(err, msg, args...)}
 }
 
@@ -50,7 +51,7 @@ func New(msg string) error {
 }
 
 // Newf creates an InternalError error with formatted message
-func Newf(msg string, args ...interface{}) error {
+func Newf(msg string, args ...any) error {
 	return customError{
 		code:          InternalError,
 		originalError: errors.New(fmt.Sprintf(msg, args...)),
@@ -58,7 +59,7 @@ func Newf(msg string, args ...interface{}) error {
 }
 
 // Wrapf an error with format string
-func Wrapf(err error, msg string, args ...interface{}) error {
+func Wrapf(err error, msg string, args ...any) error {
 	wrappedError := errors.Wrapf(err, msg, args...)
 
 	var customErr customError
diff --git a/errors_test.go b/errors_test.go
index b49cd8e..207c8d3 100644
--- a/errors_test.go
+++ b/errors_test.go
@@ -72,6 +72,16 @@ var _ = Describe("Errors", func() {
 		Expect(fmt.Sprintf("%+v", errors.StackTrace(err))).To(ContainSubstring("/errors_test.go:"))
 	})
 
+	It("create an unprocessable content error", func() {
+		msg := "an error with a message"
+		err := errors.UnprocessableContent.New(msg)
+
+		Expect(errors.Code(err)).To(Equal(errors.UnprocessableContent))
+		Expect(err.Error()).To(Equal(msg))
+		Expect(errors.DisplayMessage(err)).To(Equal("Unprocessable Content"))
+		Expect(fmt.Sprintf("%+v", errors.StackTrace(err))).To(ContainSubstring("/errors_test.go:"))
+	})
+
 	It("creates an Unknown error", func() {
 		msg := "an error with a message"
 		err := errors.Unknown.New(msg)
diff --git a/exports_113.go b/exports.go
similarity index 74%
rename from exports_113.go
rename to exports.go
index fa14a8f..cd68999 100644
--- a/exports_113.go
+++ b/exports.go
@@ -1,6 +1,3 @@
-//go:build go1.13
-// +build go1.13
-
 package errors
 
 import "errors"
@@ -9,4 +6,5 @@ var (
 	Is     = errors.Is
 	As     = errors.As
 	Unwrap = errors.Unwrap
+	Join   = errors.Join
 )
diff --git a/exports_120.go b/exports_120.go
deleted file mode 100644
index 41e7a71..0000000
--- a/exports_120.go
+++ /dev/null
@@ -1,10 +0,0 @@
-//go:build go1.20
-// +build go1.20
-
-package errors
-
-import "errors"
-
-var (
-	Join = errors.Join
-)
diff --git a/go.mod b/go.mod
index 1186b83..3fd7b21 100644
--- a/go.mod
+++ b/go.mod
@@ -1,9 +1,20 @@
 module github.com/neighborly/go-errors
 
-go 1.13
+go 1.20
 
 require (
 	github.com/onsi/ginkgo v1.11.0
 	github.com/onsi/gomega v1.8.1
 	github.com/pkg/errors v0.9.1
 )
+
+require (
+	github.com/hpcloud/tail v1.0.0 // indirect
+	golang.org/x/net v0.0.0-20180906233101-161cd47e91fd // indirect
+	golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e // indirect
+	golang.org/x/text v0.3.0 // indirect
+	golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7 // indirect
+	gopkg.in/fsnotify.v1 v1.4.7 // indirect
+	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
+	gopkg.in/yaml.v2 v2.2.4 // indirect
+)
diff --git a/go.sum b/go.sum
index ecea431..d2beed9 100644
--- a/go.sum
+++ b/go.sum
@@ -13,7 +13,6 @@ github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd h1:nTDtHvHSdCn1m6ITfMRqtOd/9+7a3s8RBNOZ3eYZzJA=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e h1:o3PsSEY8E4eXWkXrIP9YJALUkVZqzHJT5DOasTyn8Vs=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=