diff --git a/daml-lf/archive/src/main/protobuf/com/daml/daml_lf_dev/daml_lf2.proto b/daml-lf/archive/src/main/protobuf/com/daml/daml_lf_dev/daml_lf2.proto
index c96c0e07c1e3..dcb9a3226d99 100644
--- a/daml-lf/archive/src/main/protobuf/com/daml/daml_lf_dev/daml_lf2.proto
+++ b/daml-lf/archive/src/main/protobuf/com/daml/daml_lf_dev/daml_lf2.proto
@@ -1365,8 +1365,7 @@ message DefValue {
 
   Expr expr = 3;
 
-  bool is_test = 4;
-
+  bool is_test = 1000; // *Available in versions >= 2.dev*
 }
 
 message FeatureFlags {
diff --git a/daml-lf/archive/src/main/scala/com/digitalasset/daml/lf/archive/DecodeV2.scala b/daml-lf/archive/src/main/scala/com/digitalasset/daml/lf/archive/DecodeV2.scala
index 3c336b836efa..3389448d80d4 100644
--- a/daml-lf/archive/src/main/scala/com/digitalasset/daml/lf/archive/DecodeV2.scala
+++ b/daml-lf/archive/src/main/scala/com/digitalasset/daml/lf/archive/DecodeV2.scala
@@ -409,6 +409,9 @@ private[archive] class DecodeV2(minor: LV.Minor) {
     }
 
     private def decodeDefValue(lfValue: PLF.DefValue): Work[DValue] = {
+      if (lfValue.getIsTest) {
+        assertSince(LV.Features.scenarios, "is_test")
+      }
       val name = getInternedDottedName(lfValue.getNameWithType.getNameInternedDname)
       decodeType(lfValue.getNameWithType.getType) { typ =>
         decodeExpr(lfValue.getExpr, name.toString) { body =>
diff --git a/daml-lf/encoder/src/main/scala/com/digitalasset/daml/lf/archive/testing/EncodeV2.scala b/daml-lf/encoder/src/main/scala/com/digitalasset/daml/lf/archive/testing/EncodeV2.scala
index 174b83dc8b3d..16230c578e66 100644
--- a/daml-lf/encoder/src/main/scala/com/digitalasset/daml/lf/archive/testing/EncodeV2.scala
+++ b/daml-lf/encoder/src/main/scala/com/digitalasset/daml/lf/archive/testing/EncodeV2.scala
@@ -852,6 +852,9 @@ private[daml] class EncodeV2(minorLanguageVersion: LV.Minor) {
 
     private implicit def encodeValueDef(nameWithDef: (DottedName, DValue)): PLF.DefValue = {
       val (dottedName, value) = nameWithDef
+      if (value.isTest) {
+        assertSince(LV.Features.scenarios, "Value.isTest")
+      }
       PLF.DefValue
         .newBuilder()
         .setNameWithType(dottedName -> value.typ)