diff --git a/.golangci.yml b/.golangci.yml
index 4db9da06965c..da160ae7b3ee 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -26,12 +26,12 @@ linters-settings:
             desc: use `github.com/jackc/pgx/v5` package instead
           - pkg: github.com/jackc/pgx/v4
             desc: use `github.com/jackc/pgx/v5` package instead
-      bson:
+      oldbson:
         files:
           - $all
-          - "!**/internal/bson2/*_test.go"
+          - "!**/internal/bson2/bson2_test.go"
         deny:
-          - pkg: github.com/FerretDB/FerretDB/internal/bson$
+          - pkg: github.com/FerretDB/FerretDB/internal/bson/oldbson$
       bson2:
         files:
           - $all
diff --git a/internal/bson2/bson2_test.go b/internal/bson2/bson2_test.go
index 70c94929cb67..ed73d6f7efa4 100644
--- a/internal/bson2/bson2_test.go
+++ b/internal/bson2/bson2_test.go
@@ -24,8 +24,8 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/FerretDB/FerretDB/internal/bson"
 	"github.com/FerretDB/FerretDB/internal/bson2"
+	"github.com/FerretDB/FerretDB/internal/bson2/oldbson"
 	"github.com/FerretDB/FerretDB/internal/types"
 	"github.com/FerretDB/FerretDB/internal/util/must"
 	"github.com/FerretDB/FerretDB/internal/util/testutil"
@@ -587,9 +587,9 @@ var decodeTestCases = []decodeTestCase{
 func TestNormal(t *testing.T) {
 	for _, tc := range normalTestCases {
 		t.Run(tc.name, func(t *testing.T) {
-			t.Run("bson", func(t *testing.T) {
+			t.Run("oldbson", func(t *testing.T) {
 				t.Run("ReadFrom", func(t *testing.T) {
-					var doc bson.Document
+					var doc oldbson.Document
 					buf := bufio.NewReader(bytes.NewReader(tc.raw))
 					err := doc.ReadFrom(buf)
 					require.NoError(t, err)
@@ -603,7 +603,7 @@ func TestNormal(t *testing.T) {
 				})
 
 				t.Run("MarshalBinary", func(t *testing.T) {
-					doc, err := bson.ConvertDocument(tc.tdoc)
+					doc, err := oldbson.ConvertDocument(tc.tdoc)
 					require.NoError(t, err)
 
 					raw, err := doc.MarshalBinary()
@@ -688,9 +688,9 @@ func TestDecode(t *testing.T) {
 		require.NotNil(t, tc.decodeDeepErr, "invalid test case %q", tc.name)
 
 		t.Run(tc.name, func(t *testing.T) {
-			t.Run("bson", func(t *testing.T) {
+			t.Run("oldbson", func(t *testing.T) {
 				t.Run("ReadFrom", func(t *testing.T) {
-					var doc bson.Document
+					var doc oldbson.Document
 					buf := bufio.NewReader(bytes.NewReader(tc.raw))
 					err := doc.ReadFrom(buf)
 
@@ -746,9 +746,9 @@ func TestDecode(t *testing.T) {
 func BenchmarkDocument(b *testing.B) {
 	for _, tc := range normalTestCases {
 		b.Run(tc.name, func(b *testing.B) {
-			b.Run("bson", func(b *testing.B) {
+			b.Run("oldbson", func(b *testing.B) {
 				b.Run("ReadFrom", func(b *testing.B) {
-					var doc bson.Document
+					var doc oldbson.Document
 					var buf *bufio.Reader
 					var err error
 					br := bytes.NewReader(tc.raw)
@@ -768,7 +768,7 @@ func BenchmarkDocument(b *testing.B) {
 				})
 
 				b.Run("MarshalBinary", func(b *testing.B) {
-					doc, err := bson.ConvertDocument(tc.tdoc)
+					doc, err := oldbson.ConvertDocument(tc.tdoc)
 					require.NoError(b, err)
 
 					var raw []byte
@@ -956,7 +956,7 @@ func testRawDocument(t *testing.T, rawDoc bson2.RawDocument) {
 		br := bytes.NewReader(rawDoc)
 		bufr := bufio.NewReader(br)
 
-		var doc1 bson.Document
+		var doc1 oldbson.Document
 		err1 := doc1.ReadFrom(bufr)
 
 		if err1 != nil {
@@ -994,7 +994,7 @@ func testRawDocument(t *testing.T, rawDoc bson2.RawDocument) {
 
 		// encode
 
-		doc1e, err := bson.ConvertDocument(tdoc1)
+		doc1e, err := oldbson.ConvertDocument(tdoc1)
 		require.NoError(t, err)
 
 		doc2e, err := bson2.ConvertDocument(tdoc2)
diff --git a/internal/bson/array.go b/internal/bson2/oldbson/array.go
similarity index 99%
rename from internal/bson/array.go
rename to internal/bson2/oldbson/array.go
index b720b9e5e76a..5eb1c69c91f5 100644
--- a/internal/bson/array.go
+++ b/internal/bson2/oldbson/array.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/array_test.go b/internal/bson2/oldbson/array_test.go
similarity index 99%
rename from internal/bson/array_test.go
rename to internal/bson2/oldbson/array_test.go
index 3ca9cd617e0f..7e177a19fc53 100644
--- a/internal/bson/array_test.go
+++ b/internal/bson2/oldbson/array_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/binary.go b/internal/bson2/oldbson/binary.go
similarity index 99%
rename from internal/bson/binary.go
rename to internal/bson2/oldbson/binary.go
index 38f65bdabcc1..e7d069a850aa 100644
--- a/internal/bson/binary.go
+++ b/internal/bson2/oldbson/binary.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/binary_test.go b/internal/bson2/oldbson/binary_test.go
similarity index 99%
rename from internal/bson/binary_test.go
rename to internal/bson2/oldbson/binary_test.go
index 03741f3ee4e0..cc428bd4c493 100644
--- a/internal/bson/binary_test.go
+++ b/internal/bson2/oldbson/binary_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/bool.go b/internal/bson2/oldbson/bool.go
similarity index 99%
rename from internal/bson/bool.go
rename to internal/bson2/oldbson/bool.go
index 321dfe208741..649e3291a989 100644
--- a/internal/bson/bool.go
+++ b/internal/bson2/oldbson/bool.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/bool_test.go b/internal/bson2/oldbson/bool_test.go
similarity index 98%
rename from internal/bson/bool_test.go
rename to internal/bson2/oldbson/bool_test.go
index 4685bd8bbb6c..b843dc265529 100644
--- a/internal/bson/bool_test.go
+++ b/internal/bson2/oldbson/bool_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/cstring.go b/internal/bson2/oldbson/cstring.go
similarity index 99%
rename from internal/bson/cstring.go
rename to internal/bson2/oldbson/cstring.go
index 7fa7548bcea4..d386272f4f85 100644
--- a/internal/bson/cstring.go
+++ b/internal/bson2/oldbson/cstring.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/cstring_test.go b/internal/bson2/oldbson/cstring_test.go
similarity index 98%
rename from internal/bson/cstring_test.go
rename to internal/bson2/oldbson/cstring_test.go
index 681f61183bb2..6a9c876822c2 100644
--- a/internal/bson/cstring_test.go
+++ b/internal/bson2/oldbson/cstring_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/datetime.go b/internal/bson2/oldbson/datetime.go
similarity index 99%
rename from internal/bson/datetime.go
rename to internal/bson2/oldbson/datetime.go
index 8542b21fdf2c..9a25f5a03b25 100644
--- a/internal/bson/datetime.go
+++ b/internal/bson2/oldbson/datetime.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/datetime_test.go b/internal/bson2/oldbson/datetime_test.go
similarity index 99%
rename from internal/bson/datetime_test.go
rename to internal/bson2/oldbson/datetime_test.go
index 7b11987ed061..578f49ae0344 100644
--- a/internal/bson/datetime_test.go
+++ b/internal/bson2/oldbson/datetime_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/document.go b/internal/bson2/oldbson/document.go
similarity index 99%
rename from internal/bson/document.go
rename to internal/bson2/oldbson/document.go
index 115a5881be89..3169e6e5f6fe 100644
--- a/internal/bson/document.go
+++ b/internal/bson2/oldbson/document.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/document_test.go b/internal/bson2/oldbson/document_test.go
similarity index 99%
rename from internal/bson/document_test.go
rename to internal/bson2/oldbson/document_test.go
index dc357ca28f02..8352cf5ae768 100644
--- a/internal/bson/document_test.go
+++ b/internal/bson2/oldbson/document_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/double.go b/internal/bson2/oldbson/double.go
similarity index 99%
rename from internal/bson/double.go
rename to internal/bson2/oldbson/double.go
index 3661f2e7a5ae..5fe2eea86601 100644
--- a/internal/bson/double.go
+++ b/internal/bson2/oldbson/double.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/double_test.go b/internal/bson2/oldbson/double_test.go
similarity index 99%
rename from internal/bson/double_test.go
rename to internal/bson2/oldbson/double_test.go
index 0bc6479235b0..77412aa72135 100644
--- a/internal/bson/double_test.go
+++ b/internal/bson2/oldbson/double_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"math"
diff --git a/internal/bson/int32.go b/internal/bson2/oldbson/int32.go
similarity index 99%
rename from internal/bson/int32.go
rename to internal/bson2/oldbson/int32.go
index 81751fb577a8..8358494db011 100644
--- a/internal/bson/int32.go
+++ b/internal/bson2/oldbson/int32.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/int32_test.go b/internal/bson2/oldbson/int32_test.go
similarity index 98%
rename from internal/bson/int32_test.go
rename to internal/bson2/oldbson/int32_test.go
index db02ad320cb6..959fec248df1 100644
--- a/internal/bson/int32_test.go
+++ b/internal/bson2/oldbson/int32_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"math"
diff --git a/internal/bson/int64.go b/internal/bson2/oldbson/int64.go
similarity index 99%
rename from internal/bson/int64.go
rename to internal/bson2/oldbson/int64.go
index 9e0a00f2cfd3..751c995487dc 100644
--- a/internal/bson/int64.go
+++ b/internal/bson2/oldbson/int64.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/int64_test.go b/internal/bson2/oldbson/int64_test.go
similarity index 99%
rename from internal/bson/int64_test.go
rename to internal/bson2/oldbson/int64_test.go
index 0f1ebcbacf8d..270561ea6d0b 100644
--- a/internal/bson/int64_test.go
+++ b/internal/bson2/oldbson/int64_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"math"
diff --git a/internal/bson/null.go b/internal/bson2/oldbson/null.go
similarity index 98%
rename from internal/bson/null.go
rename to internal/bson2/oldbson/null.go
index 4b0a3ca96933..3e4be1dee6a3 100644
--- a/internal/bson/null.go
+++ b/internal/bson2/oldbson/null.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/object_id.go b/internal/bson2/oldbson/object_id.go
similarity index 99%
rename from internal/bson/object_id.go
rename to internal/bson2/oldbson/object_id.go
index 296b61c2e070..83ccb5daa4d0 100644
--- a/internal/bson/object_id.go
+++ b/internal/bson2/oldbson/object_id.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/object_id_test.go b/internal/bson2/oldbson/object_id_test.go
similarity index 98%
rename from internal/bson/object_id_test.go
rename to internal/bson2/oldbson/object_id_test.go
index da0e6b893567..6ac38dd33c5e 100644
--- a/internal/bson/object_id_test.go
+++ b/internal/bson2/oldbson/object_id_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/bson.go b/internal/bson2/oldbson/oldbson.go
similarity index 65%
rename from internal/bson/bson.go
rename to internal/bson2/oldbson/oldbson.go
index e4ca224413b3..79a74423790e 100644
--- a/internal/bson/bson.go
+++ b/internal/bson2/oldbson/oldbson.go
@@ -12,37 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package bson provides converters from/to BSON for built-in and `types` types.
-//
-// See contributing guidelines and documentation for package `types` for details.
-//
-// # Mapping
-//
-// Composite types
-//
-//	Alias      types package    bson package
-//
-//	object     *types.Document  *bson.Document
-//	array      *types.Array     *bson.arrayType
-//
-// Scalar types
-//
-//	Alias      types package    bson package
-//
-//	double     float64          *bson.doubleType
-//	string     string           *bson.stringType
-//	binData    types.Binary     *bson.binaryType
-//	objectId   types.ObjectID   *bson.objectIDType
-//	bool       bool             *bson.boolType
-//	date       time.Time        *bson.dateTimeType
-//	null       types.NullType   *bson.nullType
-//	regex      types.Regex      *bson.regexType
-//	int        int32            *bson.int32Type
-//	timestamp  types.Timestamp  *bson.timestampType
-//	long       int64            *bson.int64Type
-//
-//nolint:dupword // false positive
-package bson
+// Package oldbson contains old implementation of BSON that is used for cross-testing only.
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/bson_test.go b/internal/bson2/oldbson/oldbson_test.go
similarity index 99%
rename from internal/bson/bson_test.go
rename to internal/bson2/oldbson/oldbson_test.go
index 4a0897cd3e3c..6f6477ed1e63 100644
--- a/internal/bson/bson_test.go
+++ b/internal/bson2/oldbson/oldbson_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/regex.go b/internal/bson2/oldbson/regex.go
similarity index 99%
rename from internal/bson/regex.go
rename to internal/bson2/oldbson/regex.go
index 81c0151afdce..36c02bef104f 100644
--- a/internal/bson/regex.go
+++ b/internal/bson2/oldbson/regex.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/regex_test.go b/internal/bson2/oldbson/regex_test.go
similarity index 98%
rename from internal/bson/regex_test.go
rename to internal/bson2/oldbson/regex_test.go
index f031cd681ca4..b4490bb5c748 100644
--- a/internal/bson/regex_test.go
+++ b/internal/bson2/oldbson/regex_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/string.go b/internal/bson2/oldbson/string.go
similarity index 99%
rename from internal/bson/string.go
rename to internal/bson2/oldbson/string.go
index e5784714bf2b..f279ba679e1c 100644
--- a/internal/bson/string.go
+++ b/internal/bson2/oldbson/string.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/string_test.go b/internal/bson2/oldbson/string_test.go
similarity index 98%
rename from internal/bson/string_test.go
rename to internal/bson2/oldbson/string_test.go
index a006ed8c3926..eb8a5a7ca7f4 100644
--- a/internal/bson/string_test.go
+++ b/internal/bson2/oldbson/string_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"
diff --git a/internal/bson/tag.go b/internal/bson2/oldbson/tag.go
similarity index 98%
rename from internal/bson/tag.go
rename to internal/bson2/oldbson/tag.go
index c29fa7fe7f0a..c52ac1e7fae8 100644
--- a/internal/bson/tag.go
+++ b/internal/bson2/oldbson/tag.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 //go:generate ../../bin/stringer -linecomment -type tag
 
diff --git a/internal/bson/tag_string.go b/internal/bson2/oldbson/tag_string.go
similarity index 98%
rename from internal/bson/tag_string.go
rename to internal/bson2/oldbson/tag_string.go
index 6d154af244b7..56095d54e54e 100644
--- a/internal/bson/tag_string.go
+++ b/internal/bson2/oldbson/tag_string.go
@@ -1,6 +1,6 @@
 // Code generated by "stringer -linecomment -type tag"; DO NOT EDIT.
 
-package bson
+package oldbson
 
 import "strconv"
 
diff --git a/internal/bson/testdata/all.hex b/internal/bson2/oldbson/testdata/all.hex
similarity index 100%
rename from internal/bson/testdata/all.hex
rename to internal/bson2/oldbson/testdata/all.hex
diff --git a/internal/bson/testdata/array_all.hex b/internal/bson2/oldbson/testdata/array_all.hex
similarity index 100%
rename from internal/bson/testdata/array_all.hex
rename to internal/bson2/oldbson/testdata/array_all.hex
diff --git a/internal/bson/testdata/array_fuzz1.hex b/internal/bson2/oldbson/testdata/array_fuzz1.hex
similarity index 100%
rename from internal/bson/testdata/array_fuzz1.hex
rename to internal/bson2/oldbson/testdata/array_fuzz1.hex
diff --git a/internal/bson/testdata/handshake1.hex b/internal/bson2/oldbson/testdata/handshake1.hex
similarity index 100%
rename from internal/bson/testdata/handshake1.hex
rename to internal/bson2/oldbson/testdata/handshake1.hex
diff --git a/internal/bson/testdata/handshake2.hex b/internal/bson2/oldbson/testdata/handshake2.hex
similarity index 100%
rename from internal/bson/testdata/handshake2.hex
rename to internal/bson2/oldbson/testdata/handshake2.hex
diff --git a/internal/bson/testdata/handshake3.hex b/internal/bson2/oldbson/testdata/handshake3.hex
similarity index 100%
rename from internal/bson/testdata/handshake3.hex
rename to internal/bson2/oldbson/testdata/handshake3.hex
diff --git a/internal/bson/testdata/handshake4.hex b/internal/bson2/oldbson/testdata/handshake4.hex
similarity index 100%
rename from internal/bson/testdata/handshake4.hex
rename to internal/bson2/oldbson/testdata/handshake4.hex
diff --git a/internal/bson/timestamp.go b/internal/bson2/oldbson/timestamp.go
similarity index 99%
rename from internal/bson/timestamp.go
rename to internal/bson2/oldbson/timestamp.go
index a5c81c604aab..3dab9563ce54 100644
--- a/internal/bson/timestamp.go
+++ b/internal/bson2/oldbson/timestamp.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"bufio"
diff --git a/internal/bson/timestamp_test.go b/internal/bson2/oldbson/timestamp_test.go
similarity index 98%
rename from internal/bson/timestamp_test.go
rename to internal/bson2/oldbson/timestamp_test.go
index 19a0ccc1e6e0..b63f1a255955 100644
--- a/internal/bson/timestamp_test.go
+++ b/internal/bson2/oldbson/timestamp_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package bson
+package oldbson
 
 import (
 	"testing"