diff --git a/source/file/file.go b/source/file/file.go
index 82408b99a..ee10d08d1 100644
--- a/source/file/file.go
+++ b/source/file/file.go
@@ -1,22 +1,31 @@
 package file
 
 import (
+	"net/http"
 	nurl "net/url"
 	"os"
 	"path/filepath"
 
 	"github.com/golang-migrate/migrate/v4/source"
+	"github.com/golang-migrate/migrate/v4/source/httpfs"
 )
 
 func init() {
 	source.Register("file", &File{})
 }
 
-func parseURL(url string) (string, error) {
+type File struct {
+	httpfs.PartialDriver
+	url  string
+	path string
+}
+
+func (f *File) Open(url string) (source.Driver, error) {
 	u, err := nurl.Parse(url)
 	if err != nil {
-		return "", err
+		return nil, err
 	}
+
 	// concat host and path to restore full path
 	// host might be `.`
 	p := u.Opaque
@@ -28,7 +37,7 @@ func parseURL(url string) (string, error) {
 		// default to current directory if no path
 		wd, err := os.Getwd()
 		if err != nil {
-			return "", err
+			return nil, err
 		}
 		p = wd
 
@@ -36,9 +45,17 @@ func parseURL(url string) (string, error) {
 		// make path absolute if relative
 		abs, err := filepath.Abs(p)
 		if err != nil {
-			return "", err
+			return nil, err
 		}
 		p = abs
 	}
-	return p, nil
+
+	nf := &File{
+		url:  url,
+		path: p,
+	}
+	if err := nf.Init(http.Dir(p), ""); err != nil {
+		return nil, err
+	}
+	return nf, nil
 }
diff --git a/source/file/file_go115.go b/source/file/file_go115.go
deleted file mode 100644
index e2857b364..000000000
--- a/source/file/file_go115.go
+++ /dev/null
@@ -1,32 +0,0 @@
-// +build !go1.16
-
-package file
-
-import (
-	"net/http"
-
-	"github.com/golang-migrate/migrate/v4/source"
-	"github.com/golang-migrate/migrate/v4/source/httpfs"
-)
-
-type File struct {
-	httpfs.PartialDriver
-	url  string
-	path string
-}
-
-func (f *File) Open(url string) (source.Driver, error) {
-	p, err := parseURL(url)
-	if err != nil {
-		return nil, err
-	}
-
-	nf := &File{
-		url:  url,
-		path: p,
-	}
-	if err := nf.Init(http.Dir(p), ""); err != nil {
-		return nil, err
-	}
-	return nf, nil
-}
diff --git a/source/file/file_go116.go b/source/file/file_go116.go
deleted file mode 100644
index 5203b4bdb..000000000
--- a/source/file/file_go116.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// +build go1.16
-
-package file
-
-import (
-	"os"
-
-	"github.com/golang-migrate/migrate/v4/source"
-	"github.com/golang-migrate/migrate/v4/source/iofs"
-)
-
-type File struct {
-	iofs.PartialDriver
-	url  string
-	path string
-}
-
-func (f *File) Open(url string) (source.Driver, error) {
-	p, err := parseURL(url)
-	if err != nil {
-		return nil, err
-	}
-	nf := &File{
-		url:  url,
-		path: p,
-	}
-	if err := nf.Init(os.DirFS(p), "."); err != nil {
-		return nil, err
-	}
-	return nf, nil
-}
diff --git a/source/iofs/README.md b/source/iofs/README.md
deleted file mode 100644
index d75b328b9..000000000
--- a/source/iofs/README.md
+++ /dev/null
@@ -1,3 +0,0 @@
-# iofs
-
-https://pkg.go.dev/github.com/golang-migrate/migrate/v4/source/iofs
diff --git a/source/iofs/doc.go b/source/iofs/doc.go
deleted file mode 100644
index 6b2c862e0..000000000
--- a/source/iofs/doc.go
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
-Package iofs provides the Go 1.16+ io/fs#FS driver.
-
-It can accept various file systems (like embed.FS, archive/zip#Reader) implementing io/fs#FS.
-
-This driver cannot be used with Go versions 1.15 and below.
-
-Also, Opening with a URL scheme is not supported.
-*/
-package iofs
diff --git a/source/iofs/example_test.go b/source/iofs/example_test.go
deleted file mode 100644
index 87d4e568b..000000000
--- a/source/iofs/example_test.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// +build go1.16
-
-package iofs_test
-
-import (
-	"embed"
-	"log"
-
-	"github.com/golang-migrate/migrate/v4"
-	_ "github.com/golang-migrate/migrate/v4/database/postgres"
-	"github.com/golang-migrate/migrate/v4/source/iofs"
-)
-
-//go:embed testdata/migrations/*.sql
-var fs embed.FS
-
-func Example() {
-	d, err := iofs.New(fs, "testdata/migrations")
-	if err != nil {
-		log.Fatal(err)
-	}
-	m, err := migrate.NewWithSourceInstance("iofs", d, "postgres://postgres@localhost/postgres?sslmode=disable")
-	if err != nil {
-		log.Fatal(err)
-	}
-	err = m.Up()
-	if err != nil {
-		// ...
-	}
-	// ...
-}
diff --git a/source/iofs/iofs.go b/source/iofs/iofs.go
deleted file mode 100644
index f76e44387..000000000
--- a/source/iofs/iofs.go
+++ /dev/null
@@ -1,175 +0,0 @@
-// +build go1.16
-
-package iofs
-
-import (
-	"errors"
-	"fmt"
-	"io"
-	"io/fs"
-	"path"
-	"strconv"
-
-	"github.com/golang-migrate/migrate/v4/source"
-)
-
-type driver struct {
-	PartialDriver
-}
-
-// New returns a new Driver from io/fs#FS and a relative path.
-func New(fsys fs.FS, path string) (source.Driver, error) {
-	var i driver
-	if err := i.Init(fsys, path); err != nil {
-		return nil, fmt.Errorf("failed to init driver with path %s: %w", path, err)
-	}
-	return &i, nil
-}
-
-// Open is part of source.Driver interface implementation.
-// Open cannot be called on the iofs passthrough driver.
-func (d *driver) Open(url string) (source.Driver, error) {
-	return nil, errors.New("Open() cannot be called on the iofs passthrough driver")
-}
-
-// PartialDriver is a helper service for creating new source drivers working with
-// io/fs.FS instances. It implements all source.Driver interface methods
-// except for Open(). New driver could embed this struct and add missing Open()
-// method.
-//
-// To prepare PartialDriver for use Init() function.
-type PartialDriver struct {
-	migrations *source.Migrations
-	fsys       fs.FS
-	path       string
-}
-
-// Init prepares not initialized IoFS instance to read migrations from a
-// io/fs#FS instance and a relative path.
-func (d *PartialDriver) Init(fsys fs.FS, path string) error {
-	entries, err := fs.ReadDir(fsys, path)
-	if err != nil {
-		return err
-	}
-
-	ms := source.NewMigrations()
-	for _, e := range entries {
-		if e.IsDir() {
-			continue
-		}
-		m, err := source.DefaultParse(e.Name())
-		if err != nil {
-			continue
-		}
-		file, err := e.Info()
-		if err != nil {
-			return err
-		}
-		if !ms.Append(m) {
-			return source.ErrDuplicateMigration{
-				Migration: *m,
-				FileInfo:  file,
-			}
-		}
-	}
-
-	d.fsys = fsys
-	d.path = path
-	d.migrations = ms
-	return nil
-}
-
-// Close is part of source.Driver interface implementation.
-// Closes the file system if possible.
-func (d *PartialDriver) Close() error {
-	c, ok := d.fsys.(io.Closer)
-	if !ok {
-		return nil
-	}
-	return c.Close()
-}
-
-// First is part of source.Driver interface implementation.
-func (d *PartialDriver) First() (version uint, err error) {
-	if version, ok := d.migrations.First(); ok {
-		return version, nil
-	}
-	return 0, &fs.PathError{
-		Op:   "first",
-		Path: d.path,
-		Err:  fs.ErrNotExist,
-	}
-}
-
-// Prev is part of source.Driver interface implementation.
-func (d *PartialDriver) Prev(version uint) (prevVersion uint, err error) {
-	if version, ok := d.migrations.Prev(version); ok {
-		return version, nil
-	}
-	return 0, &fs.PathError{
-		Op:   "prev for version " + strconv.FormatUint(uint64(version), 10),
-		Path: d.path,
-		Err:  fs.ErrNotExist,
-	}
-}
-
-// Next is part of source.Driver interface implementation.
-func (d *PartialDriver) Next(version uint) (nextVersion uint, err error) {
-	if version, ok := d.migrations.Next(version); ok {
-		return version, nil
-	}
-	return 0, &fs.PathError{
-		Op:   "next for version " + strconv.FormatUint(uint64(version), 10),
-		Path: d.path,
-		Err:  fs.ErrNotExist,
-	}
-}
-
-// ReadUp is part of source.Driver interface implementation.
-func (d *PartialDriver) ReadUp(version uint) (r io.ReadCloser, identifier string, err error) {
-	if m, ok := d.migrations.Up(version); ok {
-		body, err := d.open(path.Join(d.path, m.Raw))
-		if err != nil {
-			return nil, "", err
-		}
-		return body, m.Identifier, nil
-	}
-	return nil, "", &fs.PathError{
-		Op:   "read up for version " + strconv.FormatUint(uint64(version), 10),
-		Path: d.path,
-		Err:  fs.ErrNotExist,
-	}
-}
-
-// ReadDown is part of source.Driver interface implementation.
-func (d *PartialDriver) ReadDown(version uint) (r io.ReadCloser, identifier string, err error) {
-	if m, ok := d.migrations.Down(version); ok {
-		body, err := d.open(path.Join(d.path, m.Raw))
-		if err != nil {
-			return nil, "", err
-		}
-		return body, m.Identifier, nil
-	}
-	return nil, "", &fs.PathError{
-		Op:   "read down for version " + strconv.FormatUint(uint64(version), 10),
-		Path: d.path,
-		Err:  fs.ErrNotExist,
-	}
-}
-
-func (d *PartialDriver) open(path string) (fs.File, error) {
-	f, err := d.fsys.Open(path)
-	if err == nil {
-		return f, nil
-	}
-	// Some non-standard file systems may return errors that don't include the path, that
-	// makes debugging harder.
-	if !errors.As(err, new(*fs.PathError)) {
-		err = &fs.PathError{
-			Op:   "open",
-			Path: path,
-			Err:  err,
-		}
-	}
-	return nil, err
-}
diff --git a/source/iofs/iofs_test.go b/source/iofs/iofs_test.go
deleted file mode 100644
index 2e0def2c7..000000000
--- a/source/iofs/iofs_test.go
+++ /dev/null
@@ -1,22 +0,0 @@
-// +build go1.16
-
-package iofs_test
-
-import (
-	"embed"
-	"testing"
-
-	"github.com/golang-migrate/migrate/v4/source/iofs"
-	st "github.com/golang-migrate/migrate/v4/source/testing"
-)
-
-func Test(t *testing.T) {
-	//go:embed testdata/migrations/*.sql
-	var fs embed.FS
-	d, err := iofs.New(fs, "testdata/migrations")
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	st.Test(t, d)
-}
diff --git a/source/iofs/testdata/migrations/1_foobar.down.sql b/source/iofs/testdata/migrations/1_foobar.down.sql
deleted file mode 100644
index 4267951a5..000000000
--- a/source/iofs/testdata/migrations/1_foobar.down.sql
+++ /dev/null
@@ -1 +0,0 @@
-1 down
diff --git a/source/iofs/testdata/migrations/1_foobar.up.sql b/source/iofs/testdata/migrations/1_foobar.up.sql
deleted file mode 100644
index 046fd5a5d..000000000
--- a/source/iofs/testdata/migrations/1_foobar.up.sql
+++ /dev/null
@@ -1 +0,0 @@
-1 up
diff --git a/source/iofs/testdata/migrations/3_foobar.up.sql b/source/iofs/testdata/migrations/3_foobar.up.sql
deleted file mode 100644
index 77c1b77dc..000000000
--- a/source/iofs/testdata/migrations/3_foobar.up.sql
+++ /dev/null
@@ -1 +0,0 @@
-3 up
diff --git a/source/iofs/testdata/migrations/4_foobar.down.sql b/source/iofs/testdata/migrations/4_foobar.down.sql
deleted file mode 100644
index b405d8bd0..000000000
--- a/source/iofs/testdata/migrations/4_foobar.down.sql
+++ /dev/null
@@ -1 +0,0 @@
-4 down
diff --git a/source/iofs/testdata/migrations/4_foobar.up.sql b/source/iofs/testdata/migrations/4_foobar.up.sql
deleted file mode 100644
index eba61bb94..000000000
--- a/source/iofs/testdata/migrations/4_foobar.up.sql
+++ /dev/null
@@ -1 +0,0 @@
-4 up
diff --git a/source/iofs/testdata/migrations/5_foobar.down.sql b/source/iofs/testdata/migrations/5_foobar.down.sql
deleted file mode 100644
index 6dc96e206..000000000
--- a/source/iofs/testdata/migrations/5_foobar.down.sql
+++ /dev/null
@@ -1 +0,0 @@
-5 down
diff --git a/source/iofs/testdata/migrations/7_foobar.down.sql b/source/iofs/testdata/migrations/7_foobar.down.sql
deleted file mode 100644
index 46636016b..000000000
--- a/source/iofs/testdata/migrations/7_foobar.down.sql
+++ /dev/null
@@ -1 +0,0 @@
-7 down
diff --git a/source/iofs/testdata/migrations/7_foobar.up.sql b/source/iofs/testdata/migrations/7_foobar.up.sql
deleted file mode 100644
index cdbc410ee..000000000
--- a/source/iofs/testdata/migrations/7_foobar.up.sql
+++ /dev/null
@@ -1 +0,0 @@
-7 up