diff --git a/buildSrc/src/main/kotlin/protokt.spotless-conventions.gradle.kts b/buildSrc/src/main/kotlin/protokt.spotless-conventions.gradle.kts
index 249321bf..749a1c0d 100644
--- a/buildSrc/src/main/kotlin/protokt.spotless-conventions.gradle.kts
+++ b/buildSrc/src/main/kotlin/protokt.spotless-conventions.gradle.kts
@@ -81,6 +81,7 @@ allprojects {
                     "testing/conformance/driver/src/main/proto/conformance/conformance.proto",
                     "testing/conformance/driver/src/main/proto/protobuf_test_messages/editions/proto3/test_messages_proto3_editions.proto",
                     "testing/conformance/driver/src/main/proto/protobuf_test_messages/editions/test_messages_edition2023.proto",
+                    "testing/conformance/driver/src/main/proto/protobuf_test_messages/proto2/test_messages_proto2.proto",
                     "testing/conformance/driver/src/main/proto/protobuf_test_messages/proto3/test_messages_proto3.proto",
                     "testing/interop/src/main/proto/tutorial/addressbook.proto",
                     "testing/interop/src/main/proto/google/protobuf/unittest_import.proto",
diff --git a/testing/conformance/driver/src/commonMain/kotlin/protokt/v1/conformance/Main.kt b/testing/conformance/driver/src/commonMain/kotlin/protokt/v1/conformance/Main.kt
index 62bdc6ae..d43cf779 100644
--- a/testing/conformance/driver/src/commonMain/kotlin/protokt/v1/conformance/Main.kt
+++ b/testing/conformance/driver/src/commonMain/kotlin/protokt/v1/conformance/Main.kt
@@ -39,7 +39,7 @@ fun main() =
 private fun processRequest(request: ConformanceRequest): ConformanceStepResult<Result> {
     val skipReason = skipReason(request)
     if (skipReason != null) {
-        // Platform.printErr("Received unsupported request for message type ${request.messageType}: $skipReason")
+        Platform.printErr("Received unsupported request for message type ${request.messageType}: $skipReason")
         return ConformanceStepResult.skip()
     }
 
@@ -57,6 +57,7 @@ private fun processRequest(request: ConformanceRequest): ConformanceStepResult<R
 private val supportedMessageTypes =
     setOf(
         "protobuf_test_messages.proto3.TestAllTypesProto3",
+        "protobuf_test_messages.proto2.TestAllTypesProto2",
         "protobuf_test_messages.editions.proto3.TestAllTypesProto3",
         "protobuf_test_messages.editions.TestAllTypesEdition2023"
     )
diff --git a/testing/conformance/driver/src/main/proto/protobuf_test_messages/proto2/test_messages_proto2.proto b/testing/conformance/driver/src/main/proto/protobuf_test_messages/proto2/test_messages_proto2.proto
new file mode 100644
index 00000000..73cba558
--- /dev/null
+++ b/testing/conformance/driver/src/main/proto/protobuf_test_messages/proto2/test_messages_proto2.proto
@@ -0,0 +1,387 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+//
+// Test schema for proto2 messages.  This test schema is used by:
+//
+// - conformance tests
+//
+
+// LINT: ALLOW_GROUPS
+
+syntax = "proto2";
+
+package protobuf_test_messages.proto2;
+
+option java_package = "com.google.protobuf_test_messages.proto2";
+option objc_class_prefix = "Proto2";
+
+// This is the default, but we specify it here explicitly.
+option optimize_for = SPEED;
+
+option cc_enable_arenas = true;
+
+
+// This proto includes every type of field in both singular and repeated
+// forms.
+//
+// Also, crucially, all messages and enums in this file are eventually
+// submessages of this message.  So for example, a fuzz test of TestAllTypes
+// could trigger bugs that occur in any message type in this file.  We verify
+// this stays true in a unit test.
+message TestAllTypesProto2 {
+  message NestedMessage {
+    optional int32 a = 1;
+    optional TestAllTypesProto2 corecursive = 2;
+  }
+
+  enum NestedEnum {
+    FOO = 0;
+    BAR = 1;
+    BAZ = 2;
+    NEG = -1;  // Intentionally negative.
+  }
+
+  // Singular
+  optional int32 optional_int32 = 1;
+  optional int64 optional_int64 = 2;
+  optional uint32 optional_uint32 = 3;
+  optional uint64 optional_uint64 = 4;
+  optional sint32 optional_sint32 = 5;
+  optional sint64 optional_sint64 = 6;
+  optional fixed32 optional_fixed32 = 7;
+  optional fixed64 optional_fixed64 = 8;
+  optional sfixed32 optional_sfixed32 = 9;
+  optional sfixed64 optional_sfixed64 = 10;
+  optional float optional_float = 11;
+  optional double optional_double = 12;
+  optional bool optional_bool = 13;
+  optional string optional_string = 14;
+  optional bytes optional_bytes = 15;
+
+  optional NestedMessage optional_nested_message = 18;
+  optional ForeignMessageProto2 optional_foreign_message = 19;
+
+  optional NestedEnum optional_nested_enum = 21;
+  optional ForeignEnumProto2 optional_foreign_enum = 22;
+
+  optional string optional_string_piece = 24 [ctype = STRING_PIECE];
+  optional string optional_cord = 25 [ctype = CORD];
+
+  optional TestAllTypesProto2 recursive_message = 27;
+
+  // Repeated
+  repeated int32 repeated_int32 = 31;
+  repeated int64 repeated_int64 = 32;
+  repeated uint32 repeated_uint32 = 33;
+  repeated uint64 repeated_uint64 = 34;
+  repeated sint32 repeated_sint32 = 35;
+  repeated sint64 repeated_sint64 = 36;
+  repeated fixed32 repeated_fixed32 = 37;
+  repeated fixed64 repeated_fixed64 = 38;
+  repeated sfixed32 repeated_sfixed32 = 39;
+  repeated sfixed64 repeated_sfixed64 = 40;
+  repeated float repeated_float = 41;
+  repeated double repeated_double = 42;
+  repeated bool repeated_bool = 43;
+  repeated string repeated_string = 44;
+  repeated bytes repeated_bytes = 45;
+
+  repeated NestedMessage repeated_nested_message = 48;
+  repeated ForeignMessageProto2 repeated_foreign_message = 49;
+
+  repeated NestedEnum repeated_nested_enum = 51;
+  repeated ForeignEnumProto2 repeated_foreign_enum = 52;
+
+  repeated string repeated_string_piece = 54 [ctype = STRING_PIECE];
+  repeated string repeated_cord = 55 [ctype = CORD];
+
+  // Packed
+  repeated int32 packed_int32 = 75 [packed = true];
+  repeated int64 packed_int64 = 76 [packed = true];
+  repeated uint32 packed_uint32 = 77 [packed = true];
+  repeated uint64 packed_uint64 = 78 [packed = true];
+  repeated sint32 packed_sint32 = 79 [packed = true];
+  repeated sint64 packed_sint64 = 80 [packed = true];
+  repeated fixed32 packed_fixed32 = 81 [packed = true];
+  repeated fixed64 packed_fixed64 = 82 [packed = true];
+  repeated sfixed32 packed_sfixed32 = 83 [packed = true];
+  repeated sfixed64 packed_sfixed64 = 84 [packed = true];
+  repeated float packed_float = 85 [packed = true];
+  repeated double packed_double = 86 [packed = true];
+  repeated bool packed_bool = 87 [packed = true];
+  repeated NestedEnum packed_nested_enum = 88 [packed = true];
+
+  // Unpacked
+  repeated int32 unpacked_int32 = 89 [packed = false];
+  repeated int64 unpacked_int64 = 90 [packed = false];
+  repeated uint32 unpacked_uint32 = 91 [packed = false];
+  repeated uint64 unpacked_uint64 = 92 [packed = false];
+  repeated sint32 unpacked_sint32 = 93 [packed = false];
+  repeated sint64 unpacked_sint64 = 94 [packed = false];
+  repeated fixed32 unpacked_fixed32 = 95 [packed = false];
+  repeated fixed64 unpacked_fixed64 = 96 [packed = false];
+  repeated sfixed32 unpacked_sfixed32 = 97 [packed = false];
+  repeated sfixed64 unpacked_sfixed64 = 98 [packed = false];
+  repeated float unpacked_float = 99 [packed = false];
+  repeated double unpacked_double = 100 [packed = false];
+  repeated bool unpacked_bool = 101 [packed = false];
+  repeated NestedEnum unpacked_nested_enum = 102 [packed = false];
+
+  // Map
+  map<int32, int32> map_int32_int32 = 56;
+  map<int64, int64> map_int64_int64 = 57;
+  map<uint32, uint32> map_uint32_uint32 = 58;
+  map<uint64, uint64> map_uint64_uint64 = 59;
+  map<sint32, sint32> map_sint32_sint32 = 60;
+  map<sint64, sint64> map_sint64_sint64 = 61;
+  map<fixed32, fixed32> map_fixed32_fixed32 = 62;
+  map<fixed64, fixed64> map_fixed64_fixed64 = 63;
+  map<sfixed32, sfixed32> map_sfixed32_sfixed32 = 64;
+  map<sfixed64, sfixed64> map_sfixed64_sfixed64 = 65;
+  map<int32, float> map_int32_float = 66;
+  map<int32, double> map_int32_double = 67;
+  map<bool, bool> map_bool_bool = 68;
+  map<string, string> map_string_string = 69;
+  map<string, bytes> map_string_bytes = 70;
+  map<string, NestedMessage> map_string_nested_message = 71;
+  map<string, ForeignMessageProto2> map_string_foreign_message = 72;
+  map<string, NestedEnum> map_string_nested_enum = 73;
+  map<string, ForeignEnumProto2> map_string_foreign_enum = 74;
+
+  oneof oneof_field {
+    uint32 oneof_uint32 = 111;
+    NestedMessage oneof_nested_message = 112;
+    string oneof_string = 113;
+    bytes oneof_bytes = 114;
+    bool oneof_bool = 115;
+    uint64 oneof_uint64 = 116;
+    float oneof_float = 117;
+    double oneof_double = 118;
+    NestedEnum oneof_enum = 119;
+  }
+
+  // extensions
+  extensions 120 to 200;
+
+  // groups
+  optional group Data = 201 {
+    optional int32 group_int32 = 202;
+    optional uint32 group_uint32 = 203;
+  }
+
+  optional group MultiWordGroupField = 204 {
+    optional int32 group_int32 = 205;
+    optional uint32 group_uint32 = 206;
+  }
+
+  // default values
+  optional int32 default_int32 = 241 [default = -123456789];
+  optional int64 default_int64 = 242 [default = -9123456789123456789];
+  optional uint32 default_uint32 = 243 [default = 2123456789];
+  optional uint64 default_uint64 = 244 [default = 10123456789123456789];
+  optional sint32 default_sint32 = 245 [default = -123456789];
+  optional sint64 default_sint64 = 246 [default = -9123456789123456789];
+  optional fixed32 default_fixed32 = 247 [default = 2123456789];
+  optional fixed64 default_fixed64 = 248 [default = 10123456789123456789];
+  optional sfixed32 default_sfixed32 = 249 [default = -123456789];
+  optional sfixed64 default_sfixed64 = 250 [default = -9123456789123456789];
+  optional float default_float = 251 [default = 9e9];
+  optional double default_double = 252 [default = 7e22];
+  optional bool default_bool = 253 [default = true];
+  optional string default_string = 254 [default = "Rosebud"];
+  optional bytes default_bytes = 255 [default = "joshua"];
+
+  // Test field-name-to-JSON-name convention.
+  // (protobuf says names can be any valid C/C++ identifier.)
+  optional int32 fieldname1 = 401;
+  optional int32 field_name2 = 402;
+  optional int32 _field_name3 = 403;
+  optional int32 field__name4_ = 404;
+  optional int32 field0name5 = 405;
+  optional int32 field_0_name6 = 406;
+  optional int32 fieldName7 = 407;
+  optional int32 FieldName8 = 408;
+  optional int32 field_Name9 = 409;
+  optional int32 Field_Name10 = 410;
+  optional int32 FIELD_NAME11 = 411;
+  optional int32 FIELD_name12 = 412;
+  optional int32 __field_name13 = 413;
+  optional int32 __Field_name14 = 414;
+  optional int32 field__name15 = 415;
+  optional int32 field__Name16 = 416;
+  optional int32 field_name17__ = 417;
+  optional int32 Field_name18__ = 418;
+
+  // Reserved for unknown fields test.
+  reserved 1000 to 9999;
+
+  // message_set test case.
+  message MessageSetCorrect {
+    option message_set_wire_format = true;
+
+    extensions 4 to max;
+  }
+
+  message MessageSetCorrectExtension1 {
+    extend MessageSetCorrect {
+      optional MessageSetCorrectExtension1 message_set_extension = 1547769;
+    }
+    optional string str = 25;
+  }
+
+  message MessageSetCorrectExtension2 {
+    extend MessageSetCorrect {
+      optional MessageSetCorrectExtension2 message_set_extension = 4135312;
+    }
+    optional int32 i = 9;
+  }
+}
+
+message ForeignMessageProto2 {
+  optional int32 c = 1;
+}
+
+enum ForeignEnumProto2 {
+  FOREIGN_FOO = 0;
+  FOREIGN_BAR = 1;
+  FOREIGN_BAZ = 2;
+}
+
+extend TestAllTypesProto2 {
+  optional int32 extension_int32 = 120;
+}
+
+extend TestAllTypesProto2 {
+  optional group GroupField = 121 {
+    optional int32 group_int32 = 122;
+    optional uint32 group_uint32 = 123;
+  }
+}
+
+message UnknownToTestAllTypes {
+  optional int32 optional_int32 = 1001;
+  optional string optional_string = 1002;
+  optional ForeignMessageProto2 nested_message = 1003;
+  optional group OptionalGroup = 1004 {
+    optional int32 a = 1;
+  }
+  optional bool optional_bool = 1006;
+  repeated int32 repeated_int32 = 1011;
+}
+
+message NullHypothesisProto2 {}
+
+message EnumOnlyProto2 {
+  enum Bool {
+    kFalse = 0;
+    kTrue = 1;
+  }
+}
+
+message OneStringProto2 {
+  optional string data = 1;
+}
+
+message ProtoWithKeywords {
+  optional int32 inline = 1;
+  optional string concept = 2;
+  repeated string requires = 3;
+}
+
+message TestAllRequiredTypesProto2 {
+  message NestedMessage {
+    required int32 a = 1;
+    required TestAllRequiredTypesProto2 corecursive = 2;
+    optional TestAllRequiredTypesProto2 optional_corecursive = 3;
+  }
+
+  enum NestedEnum {
+    FOO = 0;
+    BAR = 1;
+    BAZ = 2;
+    NEG = -1;  // Intentionally negative.
+  }
+
+  // Singular
+  required int32 required_int32 = 1;
+  required int64 required_int64 = 2;
+  required uint32 required_uint32 = 3;
+  required uint64 required_uint64 = 4;
+  required sint32 required_sint32 = 5;
+  required sint64 required_sint64 = 6;
+  required fixed32 required_fixed32 = 7;
+  required fixed64 required_fixed64 = 8;
+  required sfixed32 required_sfixed32 = 9;
+  required sfixed64 required_sfixed64 = 10;
+  required float required_float = 11;
+  required double required_double = 12;
+  required bool required_bool = 13;
+  required string required_string = 14;
+  required bytes required_bytes = 15;
+
+  required NestedMessage required_nested_message = 18;
+  required ForeignMessageProto2 required_foreign_message = 19;
+
+  required NestedEnum required_nested_enum = 21;
+  required ForeignEnumProto2 required_foreign_enum = 22;
+
+  required string required_string_piece = 24 [ctype = STRING_PIECE];
+  required string required_cord = 25 [ctype = CORD];
+
+  required TestAllRequiredTypesProto2 recursive_message = 27;
+  optional TestAllRequiredTypesProto2 optional_recursive_message = 28;
+
+  // extensions
+  extensions 120 to 200;
+
+  // groups
+  required group Data = 201 {
+    required int32 group_int32 = 202;
+    required uint32 group_uint32 = 203;
+  }
+
+  // default values
+  required int32 default_int32 = 241 [default = -123456789];
+  required int64 default_int64 = 242 [default = -9123456789123456789];
+  required uint32 default_uint32 = 243 [default = 2123456789];
+  required uint64 default_uint64 = 244 [default = 10123456789123456789];
+  required sint32 default_sint32 = 245 [default = -123456789];
+  required sint64 default_sint64 = 246 [default = -9123456789123456789];
+  required fixed32 default_fixed32 = 247 [default = 2123456789];
+  required fixed64 default_fixed64 = 248 [default = 10123456789123456789];
+  required sfixed32 default_sfixed32 = 249 [default = -123456789];
+  required sfixed64 default_sfixed64 = 250 [default = -9123456789123456789];
+  required float default_float = 251 [default = 9e9];
+  required double default_double = 252 [default = 7e22];
+  required bool default_bool = 253 [default = true];
+  required string default_string = 254 [default = "Rosebud"];
+  required bytes default_bytes = 255 [default = "joshua"];
+
+  // Reserved for unknown fields test.
+  reserved 1000 to 9999;
+
+  // message_set test case.
+  message MessageSetCorrect {
+    option message_set_wire_format = true;
+
+    extensions 4 to max;
+  }
+
+  message MessageSetCorrectExtension1 {
+    extend MessageSetCorrect {
+      optional MessageSetCorrectExtension1 message_set_extension = 1547769;
+    }
+    required string str = 25;
+  }
+
+  message MessageSetCorrectExtension2 {
+    extend MessageSetCorrect {
+      optional MessageSetCorrectExtension2 message_set_extension = 4135312;
+    }
+    required int32 i = 9;
+  }
+}