diff --git a/jps/jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/incremental/AbstractJsProtoComparisonTest.kt b/jps/jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/incremental/AbstractJsProtoComparisonTest.kt
index 84f33f57bf3..b5604496c61 100644
--- a/jps/jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/incremental/AbstractJsProtoComparisonTest.kt
+++ b/jps/jps-plugin/jps-tests/test/org/jetbrains/kotlin/jps/incremental/AbstractJsProtoComparisonTest.kt
@@ -52,6 +52,7 @@ abstract class AbstractJsProtoComparisonTest : AbstractProtoComparisonTest<Proto
             main = K2JsArgumentConstants.NO_CALL
             freeArgs = ktFiles
             forceDeprecatedLegacyCompilerUsage = true
+            languageVersion = "1.9"
         }
 
         val env = createTestingCompilerEnvironment(messageCollector, outputItemsCollector, services)