diff --git a/extensions/BUILD b/extensions/BUILD
index 1e6e9204a..fe97af46a 100644
--- a/extensions/BUILD
+++ b/extensions/BUILD
@@ -75,6 +75,7 @@ cc_library(
     srcs = ["math_ext.cc"],
     hdrs = ["math_ext.h"],
     deps = [
+        ":math_ext_decls",
         "//common:casting",
         "//common:value",
         "//eval/public:cel_function_registry",
diff --git a/extensions/math_ext.cc b/extensions/math_ext.cc
index 7b3655de3..4d133d90c 100644
--- a/extensions/math_ext.cc
+++ b/extensions/math_ext.cc
@@ -308,7 +308,8 @@ Value BitShiftRightUint(uint64_t lhs, int64_t rhs) {
 }  // namespace
 
 absl::Status RegisterMathExtensionFunctions(FunctionRegistry& registry,
-                                            const RuntimeOptions& options) {
+                                            const RuntimeOptions& options,
+                                            int version) {
   CEL_RETURN_IF_ERROR(
       (UnaryFunctionAdapter<Value, int64_t>::RegisterGlobalOverload(
           kMathMin, Identity<int64_t>, registry)));
@@ -360,6 +361,9 @@ absl::Status RegisterMathExtensionFunctions(FunctionRegistry& registry,
       UnaryFunctionAdapter<absl::StatusOr<Value>,
                            ListValue>::RegisterGlobalOverload(kMathMax, MaxList,
                                                               registry)));
+  if (version == 0) {
+    return absl::OkStatus();
+  }
 
   CEL_RETURN_IF_ERROR(
       (UnaryFunctionAdapter<double, double>::RegisterGlobalOverload(
@@ -370,15 +374,6 @@ absl::Status RegisterMathExtensionFunctions(FunctionRegistry& registry,
   CEL_RETURN_IF_ERROR(
       (UnaryFunctionAdapter<double, double>::RegisterGlobalOverload(
           "math.round", RoundDouble, registry)));
-  CEL_RETURN_IF_ERROR(
-      (UnaryFunctionAdapter<double, double>::RegisterGlobalOverload(
-          "math.sqrt", SqrtDouble, registry)));
-  CEL_RETURN_IF_ERROR(
-      (UnaryFunctionAdapter<double, int64_t>::RegisterGlobalOverload(
-          "math.sqrt", SqrtInt, registry)));
-  CEL_RETURN_IF_ERROR(
-      (UnaryFunctionAdapter<double, uint64_t>::RegisterGlobalOverload(
-          "math.sqrt", SqrtUint, registry)));
   CEL_RETURN_IF_ERROR(
       (UnaryFunctionAdapter<double, double>::RegisterGlobalOverload(
           "math.trunc", TruncDouble, registry)));
@@ -453,6 +448,20 @@ absl::Status RegisterMathExtensionFunctions(FunctionRegistry& registry,
       (BinaryFunctionAdapter<Value, uint64_t, int64_t>::RegisterGlobalOverload(
           "math.bitShiftRight", BitShiftRightUint, registry)));
 
+  if (version == 1) {
+    return absl::OkStatus();
+  }
+
+  CEL_RETURN_IF_ERROR(
+      (UnaryFunctionAdapter<double, double>::RegisterGlobalOverload(
+          "math.sqrt", SqrtDouble, registry)));
+  CEL_RETURN_IF_ERROR(
+      (UnaryFunctionAdapter<double, int64_t>::RegisterGlobalOverload(
+          "math.sqrt", SqrtInt, registry)));
+  CEL_RETURN_IF_ERROR(
+      (UnaryFunctionAdapter<double, uint64_t>::RegisterGlobalOverload(
+          "math.sqrt", SqrtUint, registry)));
+
   return absl::OkStatus();
 }
 
diff --git a/extensions/math_ext.h b/extensions/math_ext.h
index 63d9e964b..fe000e476 100644
--- a/extensions/math_ext.h
+++ b/extensions/math_ext.h
@@ -18,6 +18,7 @@
 #include "absl/status/status.h"
 #include "eval/public/cel_function_registry.h"
 #include "eval/public/cel_options.h"
+#include "extensions/math_ext_decls.h"
 #include "runtime/function_registry.h"
 #include "runtime/runtime_options.h"
 
@@ -25,8 +26,9 @@ namespace cel::extensions {
 
 // Register extension functions for supporting mathematical operations above
 // and beyond the set defined in the CEL standard environment.
-absl::Status RegisterMathExtensionFunctions(FunctionRegistry& registry,
-                                            const RuntimeOptions& options);
+absl::Status RegisterMathExtensionFunctions(
+    FunctionRegistry& registry, const RuntimeOptions& options,
+    int version = kMathExtensionLatestVersion);
 
 absl::Status RegisterMathExtensionFunctions(
     google::api::expr::runtime::CelFunctionRegistry* registry,
diff --git a/extensions/strings.cc b/extensions/strings.cc
index 652c72572..ed6f27319 100644
--- a/extensions/strings.cc
+++ b/extensions/strings.cc
@@ -306,17 +306,8 @@ absl::Status RegisterStringsDecls(TypeCheckerBuilder& builder, int version) {
 }  // namespace
 
 absl::Status RegisterStringsFunctions(FunctionRegistry& registry,
-                                      const RuntimeOptions& options) {
-  CEL_RETURN_IF_ERROR(registry.Register(
-      UnaryFunctionAdapter<absl::StatusOr<Value>, ListValue>::CreateDescriptor(
-          "join", /*receiver_style=*/true),
-      UnaryFunctionAdapter<absl::StatusOr<Value>, ListValue>::WrapFunction(
-          Join1)));
-  CEL_RETURN_IF_ERROR(registry.Register(
-      BinaryFunctionAdapter<absl::StatusOr<Value>, ListValue, StringValue>::
-          CreateDescriptor("join", /*receiver_style=*/true),
-      BinaryFunctionAdapter<absl::StatusOr<Value>, ListValue,
-                            StringValue>::WrapFunction(Join2)));
+                                      const RuntimeOptions& options,
+                                      int version) {
   CEL_RETURN_IF_ERROR(registry.Register(
       BinaryFunctionAdapter<absl::StatusOr<Value>, StringValue, StringValue>::
           CreateDescriptor("split", /*receiver_style=*/true),
@@ -350,7 +341,6 @@ absl::Status RegisterStringsFunctions(FunctionRegistry& registry,
           int64_t>::CreateDescriptor("replace", /*receiver_style=*/true),
       QuaternaryFunctionAdapter<absl::StatusOr<Value>, StringValue, StringValue,
                                 StringValue, int64_t>::WrapFunction(Replace2)));
-  CEL_RETURN_IF_ERROR(RegisterStringFormattingFunctions(registry, options));
   CEL_RETURN_IF_ERROR(
       (BinaryFunctionAdapter<Value, StringValue,
                              int64_t>::RegisterMemberOverload("charAt", &CharAt,
@@ -388,9 +378,32 @@ absl::Status RegisterStringsFunctions(FunctionRegistry& registry,
   CEL_RETURN_IF_ERROR(
       (UnaryFunctionAdapter<StringValue, StringValue>::RegisterMemberOverload(
           "trim", &Trim, registry)));
+  if (version == 0) {
+    return absl::OkStatus();
+  }
+
+  CEL_RETURN_IF_ERROR(RegisterStringFormattingFunctions(registry, options));
   CEL_RETURN_IF_ERROR(
       (UnaryFunctionAdapter<StringValue, StringValue>::RegisterGlobalOverload(
           "strings.quote", &Quote, registry)));
+  if (version == 1) {
+    return absl::OkStatus();
+  }
+
+  CEL_RETURN_IF_ERROR(registry.Register(
+      UnaryFunctionAdapter<absl::StatusOr<Value>, ListValue>::CreateDescriptor(
+          "join", /*receiver_style=*/true),
+      UnaryFunctionAdapter<absl::StatusOr<Value>, ListValue>::WrapFunction(
+          Join1)));
+  CEL_RETURN_IF_ERROR(registry.Register(
+      BinaryFunctionAdapter<absl::StatusOr<Value>, ListValue, StringValue>::
+          CreateDescriptor("join", /*receiver_style=*/true),
+      BinaryFunctionAdapter<absl::StatusOr<Value>, ListValue,
+                            StringValue>::WrapFunction(Join2)));
+  if (version == 2) {
+    return absl::OkStatus();
+  }
+
   CEL_RETURN_IF_ERROR(
       (UnaryFunctionAdapter<StringValue, StringValue>::RegisterMemberOverload(
           "reverse", &Reverse, registry)));
diff --git a/extensions/strings.h b/extensions/strings.h
index 5dab33c5d..3cbc9f19f 100644
--- a/extensions/strings.h
+++ b/extensions/strings.h
@@ -28,8 +28,9 @@ namespace cel::extensions {
 constexpr int kStringsExtensionLatestVersion = 4;
 
 // Register extension functions for strings.
-absl::Status RegisterStringsFunctions(FunctionRegistry& registry,
-                                      const RuntimeOptions& options);
+absl::Status RegisterStringsFunctions(
+    FunctionRegistry& registry, const RuntimeOptions& options,
+    int version = kStringsExtensionLatestVersion);
 
 absl::Status RegisterStringsFunctions(
     google::api::expr::runtime::CelFunctionRegistry* registry,