diff --git a/libmemunreachable/MemUnreachable.cpp b/libmemunreachable/MemUnreachable.cpp
index 299c320ac..ce937fd81 100644
--- a/libmemunreachable/MemUnreachable.cpp
+++ b/libmemunreachable/MemUnreachable.cpp
@@ -280,6 +280,12 @@ static inline const char* plural(T val) {
 }
 
 bool GetUnreachableMemory(UnreachableMemoryInfo& info, size_t limit) {
+  if (info.version > 0) {
+    MEM_ALOGE("unsupported UnreachableMemoryInfo.version %zu in GetUnreachableMemory",
+              info.version);
+    return false;
+  }
+
   int parent_pid = getpid();
   int parent_tid = gettid();
 
diff --git a/libmemunreachable/include/memunreachable/memunreachable.h b/libmemunreachable/include/memunreachable/memunreachable.h
index c028eabf2..011443fe3 100644
--- a/libmemunreachable/include/memunreachable/memunreachable.h
+++ b/libmemunreachable/include/memunreachable/memunreachable.h
@@ -28,38 +28,45 @@
 namespace android {
 
 struct Leak {
-  uintptr_t begin;
-  size_t size;
+  uintptr_t begin = 0;
+  size_t size = 0;
 
-  size_t referenced_count;
-  size_t referenced_size;
+  size_t referenced_count = 0;
+  size_t referenced_size = 0;
 
-  size_t similar_count;
-  size_t similar_size;
-  size_t similar_referenced_count;
-  size_t similar_referenced_size;
+  size_t similar_count = 0;
+  size_t similar_size = 0;
+  size_t similar_referenced_count = 0;
+  size_t similar_referenced_size = 0;
 
-  size_t total_size;
+  size_t total_size = 0;
 
   static const size_t contents_length = 32;
-  char contents[contents_length];
+  char contents[contents_length] = {};
 
   struct Backtrace {
-    size_t num_frames;
+    size_t num_frames = 0;
 
     static const size_t max_frames = 16;
-    uintptr_t frames[max_frames];
+    uintptr_t frames[max_frames] = {};
+
+    size_t reserved[8] = {};
   } backtrace;
 
+  size_t reserved[8] = {};
+
   std::string ToString(bool log_contents) const;
 };
 
 struct UnreachableMemoryInfo {
   std::vector<Leak> leaks;
-  size_t num_leaks;
-  size_t leak_bytes;
-  size_t num_allocations;
-  size_t allocation_bytes;
+  size_t num_leaks = 0;
+  size_t leak_bytes = 0;
+  size_t num_allocations = 0;
+  size_t allocation_bytes = 0;
+
+  size_t version = 0;  // Must be 0
+  size_t reserved[8] = {};
 
   UnreachableMemoryInfo() {}
   ~UnreachableMemoryInfo();
diff --git a/libmemunreachable/tests/MemUnreachable_test.cpp b/libmemunreachable/tests/MemUnreachable_test.cpp
index bba0c6d11..e464872e2 100644
--- a/libmemunreachable/tests/MemUnreachable_test.cpp
+++ b/libmemunreachable/tests/MemUnreachable_test.cpp
@@ -264,4 +264,12 @@ TEST_F(MemunreachableTest, leak_lots) {
   ASSERT_TRUE(LogUnreachableMemory(true, 100));
 }
 
+TEST_F(MemunreachableTest, version) {
+  UnreachableMemoryInfo info;
+  info.version = 1;
+
+  ASSERT_FALSE(GetUnreachableMemory(info));
+  ASSERT_EQ(0U, info.leaks.size());
+}
+
 }  // namespace android