diff --git a/go/test_platform/request.pb.go b/go/test_platform/request.pb.go
index d0ef14e..816a397 100644
--- a/go/test_platform/request.pb.go
+++ b/go/test_platform/request.pb.go
@@ -137,7 +137,6 @@
 	Metadata             *Request_Params_Metadata             `protobuf:"bytes,6,opt,name=metadata,proto3" json:"metadata,omitempty"`
 	Time                 *Request_Params_Time                 `protobuf:"bytes,7,opt,name=time,proto3" json:"time,omitempty"`
 	Decorations          *Request_Params_Decorations          `protobuf:"bytes,8,opt,name=decorations,proto3" json:"decorations,omitempty"`
-	Legacy               *Request_Params_Legacy               `protobuf:"bytes,10,opt,name=legacy,proto3" json:"legacy,omitempty"`
 	Migrations           *Request_Params_Migrations           `protobuf:"bytes,12,opt,name=migrations,proto3" json:"migrations,omitempty"`
 	// Uniformly applied parameters for all test executions in this request.
 	ExecutionParam       *execution.Param `protobuf:"bytes,13,opt,name=execution_param,json=executionParam,proto3" json:"execution_param,omitempty"`
@@ -234,13 +233,6 @@
 	return nil
 }
 
-func (m *Request_Params) GetLegacy() *Request_Params_Legacy {
-	if m != nil {
-		return m.Legacy
-	}
-	return nil
-}
-
 func (m *Request_Params) GetMigrations() *Request_Params_Migrations {
 	if m != nil {
 		return m.Migrations
@@ -794,50 +786,6 @@
 	return nil
 }
 
-// Legacy encodes arguments that relate to migration from legacy backend
-// (autotest); support for these arguments will be phased out.
-type Request_Params_Legacy struct {
-	// If autotest_suite is defined, then if the autotest backend is selected
-	// for running this request, the entire enumeration will be ignored, and
-	// replaced by a single invocation of this named autotest suite.
-	AutotestSuite        string   `protobuf:"bytes,1,opt,name=autotest_suite,json=autotestSuite,proto3" json:"autotest_suite,omitempty"`
-	XXX_NoUnkeyedLiteral struct{} `json:"-"`
-	XXX_unrecognized     []byte   `json:"-"`
-	XXX_sizecache        int32    `json:"-"`
-}
-
-func (m *Request_Params_Legacy) Reset()         { *m = Request_Params_Legacy{} }
-func (m *Request_Params_Legacy) String() string { return proto.CompactTextString(m) }
-func (*Request_Params_Legacy) ProtoMessage()    {}
-func (*Request_Params_Legacy) Descriptor() ([]byte, []int) {
-	return fileDescriptor_7f5ab0d1581e8f0c, []int{0, 0, 9}
-}
-
-func (m *Request_Params_Legacy) XXX_Unmarshal(b []byte) error {
-	return xxx_messageInfo_Request_Params_Legacy.Unmarshal(m, b)
-}
-func (m *Request_Params_Legacy) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
-	return xxx_messageInfo_Request_Params_Legacy.Marshal(b, m, deterministic)
-}
-func (m *Request_Params_Legacy) XXX_Merge(src proto.Message) {
-	xxx_messageInfo_Request_Params_Legacy.Merge(m, src)
-}
-func (m *Request_Params_Legacy) XXX_Size() int {
-	return xxx_messageInfo_Request_Params_Legacy.Size(m)
-}
-func (m *Request_Params_Legacy) XXX_DiscardUnknown() {
-	xxx_messageInfo_Request_Params_Legacy.DiscardUnknown(m)
-}
-
-var xxx_messageInfo_Request_Params_Legacy proto.InternalMessageInfo
-
-func (m *Request_Params_Legacy) GetAutotestSuite() string {
-	if m != nil {
-		return m.AutotestSuite
-	}
-	return ""
-}
-
 // Migrations defines parameters that facilitate gradual migrations between
 // different implementations of downstream components.
 type Request_Params_Migrations struct {
@@ -867,7 +815,7 @@
 func (m *Request_Params_Migrations) String() string { return proto.CompactTextString(m) }
 func (*Request_Params_Migrations) ProtoMessage()    {}
 func (*Request_Params_Migrations) Descriptor() ([]byte, []int) {
-	return fileDescriptor_7f5ab0d1581e8f0c, []int{0, 0, 10}
+	return fileDescriptor_7f5ab0d1581e8f0c, []int{0, 0, 9}
 }
 
 func (m *Request_Params_Migrations) XXX_Unmarshal(b []byte) error {
@@ -1251,7 +1199,6 @@
 	proto.RegisterType((*Request_Params_Time)(nil), "test_platform.Request.Params.Time")
 	proto.RegisterType((*Request_Params_Decorations)(nil), "test_platform.Request.Params.Decorations")
 	proto.RegisterMapType((map[string]string)(nil), "test_platform.Request.Params.Decorations.AutotestKeyvalsEntry")
-	proto.RegisterType((*Request_Params_Legacy)(nil), "test_platform.Request.Params.Legacy")
 	proto.RegisterType((*Request_Params_Migrations)(nil), "test_platform.Request.Params.Migrations")
 	proto.RegisterType((*Request_Suite)(nil), "test_platform.Request.Suite")
 	proto.RegisterType((*Request_Test)(nil), "test_platform.Request.Test")
@@ -1265,96 +1212,95 @@
 func init() { proto.RegisterFile("test_platform/request.proto", fileDescriptor_7f5ab0d1581e8f0c) }
 
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 }
diff --git a/src/test_platform/request.proto b/src/test_platform/request.proto
index 74dc645..36b9d53 100644
--- a/src/test_platform/request.proto
+++ b/src/test_platform/request.proto
@@ -170,17 +170,6 @@
 
     Decorations decorations = 8;
 
-    // Legacy encodes arguments that relate to migration from legacy backend
-    // (autotest); support for these arguments will be phased out.
-    message Legacy {
-      // If autotest_suite is defined, then if the autotest backend is selected
-      // for running this request, the entire enumeration will be ignored, and
-      // replaced by a single invocation of this named autotest suite.
-      string autotest_suite = 1;
-    }
-
-    Legacy legacy = 10;
-
     // Migrations defines parameters that facilitate gradual migrations between
     // different implementations of downstream components.
     message Migrations {
@@ -212,6 +201,8 @@
 
     reserved "notifications";
     reserved 11;
+    reserved "legacy";
+    reserved 10;
   }
 
   Params params = 1;