diff --git a/compiler-plugin/src/main/kotlin/com/google/devtools/ksp/IncrementalContext.kt b/compiler-plugin/src/main/kotlin/com/google/devtools/ksp/IncrementalContext.kt
index c0088e9faf..b5a91aa8fc 100644
--- a/compiler-plugin/src/main/kotlin/com/google/devtools/ksp/IncrementalContext.kt
+++ b/compiler-plugin/src/main/kotlin/com/google/devtools/ksp/IncrementalContext.kt
@@ -244,7 +244,7 @@ class LookupStorageWrapperImpl(
 
     override fun close() = impl.close()
 
-    override fun flush() = impl.flush()
+    override fun flush() = impl.flush(true)
 }
 
 object LookupSymbolExternalizer : DataExternalizer<LookupSymbolWrapper> {
diff --git a/gradle.properties b/gradle.properties
index f6c889622a..f3e55d763e 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,7 +1,7 @@
 # Copied from kotlinc
 org.gradle.jvmargs=-Duser.country=US -Dkotlin.daemon.jvm.options=-Xmx2200m -Dfile.encoding=UTF-8
 
-kotlinBaseVersion=2.0.0-Beta4
+kotlinBaseVersion=1.9.23
 agpBaseVersion=7.2.0
 intellijVersion=213.7172.25
 junitVersion=4.13.1