diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
index 8aee22645281dd..21a49ee626645b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java
@@ -710,7 +710,7 @@ public Label getFdoPrefetchHintsLabel() {
   @Option(
       name = "incompatible_disable_legacy_crosstool_fields",
       oldName = "experimental_disable_legacy_crosstool_fields",
-      defaultValue = "false",
+      defaultValue = "true",
       documentationCategory = OptionDocumentationCategory.TOOLCHAIN,
       effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
       metadataTags = {
@@ -753,7 +753,7 @@ public Label getFdoPrefetchHintsLabel() {
 
   @Option(
       name = "incompatible_disable_expand_if_all_available_in_flag_set",
-      defaultValue = "false",
+      defaultValue = "true",
       documentationCategory = OptionDocumentationCategory.TOOLCHAIN,
       effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
       metadataTags = {