diff --git a/core/Makefile b/core/Makefile
index bec8cfc..fe64d2e 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -423,6 +423,7 @@
 	        BUILD_NUMBER="$(BUILD_NUMBER_FROM_FILE)" \
 	        BOARD_BUILD_SYSTEM_ROOT_IMAGE="$(BOARD_BUILD_SYSTEM_ROOT_IMAGE)" \
 	        PLATFORM_VERSION="$(PLATFORM_VERSION)" \
+	        PLATFORM_VERSION_LAST_STABLE="$(PLATFORM_VERSION_LAST_STABLE)" \
 	        PLATFORM_SECURITY_PATCH="$(PLATFORM_SECURITY_PATCH)" \
 	        PLATFORM_BASE_OS="$(PLATFORM_BASE_OS)" \
 	        PLATFORM_SDK_VERSION="$(PLATFORM_SDK_VERSION)" \
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 8095212..ca759bb 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -84,38 +84,17 @@
 # generate the range of allowed SDK versions, so it must have an entry for every
 # unreleased API level targetable by this branch, not just those that are valid
 # lunch targets for this branch.
-PLATFORM_VERSION.RP1A := R
+
+# The last stable version name of the platform that was released.  During
+# development, this stays at that previous version, while the codename indicates
+# further work based on the previous version.
+PLATFORM_VERSION_LAST_STABLE := 10
+.KATI_READONLY := PLATFORM_VERSION_LAST_STABLE
 
 # These are the current development codenames, if the build is not a final
 # release build.  If this is a final release build, it is simply "REL".
 PLATFORM_VERSION_CODENAME.RP1A := R
 
-ifndef PLATFORM_VERSION
-  PLATFORM_VERSION := $(PLATFORM_VERSION.$(TARGET_PLATFORM_VERSION))
-  ifndef PLATFORM_VERSION
-    # PLATFORM_VERSION falls back to TARGET_PLATFORM_VERSION
-    PLATFORM_VERSION := $(TARGET_PLATFORM_VERSION)
-  endif
-endif
-.KATI_READONLY := PLATFORM_VERSION
-
-ifndef PLATFORM_SDK_VERSION
-  # This is the canonical definition of the SDK version, which defines
-  # the set of APIs and functionality available in the platform.  It
-  # is a single integer that increases monotonically as updates to
-  # the SDK are released.  It should only be incremented when the APIs for
-  # the new release are frozen (so that developers don't write apps against
-  # intermediate builds).  During development, this number remains at the
-  # SDK version the branch is based on and PLATFORM_VERSION_CODENAME holds
-  # the code-name of the new development work.
-
-  # When you increment the PLATFORM_SDK_VERSION please ensure you also
-  # clear out the following text file of all older PLATFORM_VERSION's:
-  # cts/tests/tests/os/assets/platform_versions.txt
-  PLATFORM_SDK_VERSION := 29
-endif
-.KATI_READONLY := PLATFORM_SDK_VERSION
-
 ifndef PLATFORM_VERSION_CODENAME
   PLATFORM_VERSION_CODENAME := $(PLATFORM_VERSION_CODENAME.$(TARGET_PLATFORM_VERSION))
   ifndef PLATFORM_VERSION_CODENAME
@@ -165,6 +144,32 @@
   PLATFORM_VERSION_ALL_CODENAMES \
   PLATFORM_VERSION_FUTURE_CODENAMES
 
+ifndef PLATFORM_VERSION
+  ifeq (REL,$(PLATFORM_VERSION_CODENAME))
+      PLATFORM_VERSION := $(PLATFORM_VERSION_LAST_STABLE)
+  else
+      PLATFORM_VERSION := $(PLATFORM_VERSION_CODENAME)
+  endif
+endif
+.KATI_READONLY := PLATFORM_VERSION
+
+ifndef PLATFORM_SDK_VERSION
+  # This is the canonical definition of the SDK version, which defines
+  # the set of APIs and functionality available in the platform.  It
+  # is a single integer that increases monotonically as updates to
+  # the SDK are released.  It should only be incremented when the APIs for
+  # the new release are frozen (so that developers don't write apps against
+  # intermediate builds).  During development, this number remains at the
+  # SDK version the branch is based on and PLATFORM_VERSION_CODENAME holds
+  # the code-name of the new development work.
+
+  # When you increment the PLATFORM_SDK_VERSION please ensure you also
+  # clear out the following text file of all older PLATFORM_VERSION's:
+  # cts/tests/tests/os/assets/platform_versions.txt
+  PLATFORM_SDK_VERSION := 29
+endif
+.KATI_READONLY := PLATFORM_SDK_VERSION
+
 ifeq (REL,$(PLATFORM_VERSION_CODENAME))
   PLATFORM_PREVIEW_SDK_VERSION := 0
 else
diff --git a/tools/buildinfo.sh b/tools/buildinfo.sh
index 09d8f70..9bee115 100755
--- a/tools/buildinfo.sh
+++ b/tools/buildinfo.sh
@@ -11,7 +11,8 @@
 echo "ro.build.version.preview_sdk_fingerprint=$PLATFORM_PREVIEW_SDK_FINGERPRINT"
 echo "ro.build.version.codename=$PLATFORM_VERSION_CODENAME"
 echo "ro.build.version.all_codenames=$PLATFORM_VERSION_ALL_CODENAMES"
-echo "ro.build.version.release=$PLATFORM_VERSION"
+echo "ro.build.version.release=$PLATFORM_VERSION_LAST_STABLE"
+echo "ro.build.version.release_or_codename=$PLATFORM_VERSION"
 echo "ro.build.version.security_patch=$PLATFORM_SECURITY_PATCH"
 echo "ro.build.version.base_os=$PLATFORM_BASE_OS"
 echo "ro.build.version.min_supported_target_sdk=$PLATFORM_MIN_SUPPORTED_TARGET_SDK_VERSION"