diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 2245aa2..3332fc7 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -76,12 +76,24 @@
 $(foreach v,$(ENABLED_VERSIONS), \
   $(eval IS_AT_LEAST_$(v) := true))
 
+# Default versions for each TARGET_PLATFORM_VERSION
+
+# This is the canonical definition of the platform version,
+# which is the version that we reveal to the end user.
+# Update this value when the platform version changes (rather
+# than overriding it somewhere else).  Can be an arbitrary string.
+PLATFORM_VERSION.O := O
+
+# This is the current development code-name, if the build is not a final
+# release build.  If this is a final release build, it is simply "REL".
+PLATFORM_VERSION_CODENAME.O := O
+
 ifndef PLATFORM_VERSION
-  # This is the canonical definition of the platform version,
-  # which is the version that we reveal to the end user.
-  # Update this value when the platform version changes (rather
-  # than overriding it somewhere else).  Can be an arbitrary string.
-  PLATFORM_VERSION := 7.1.1
+  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
 
 ifndef PLATFORM_SDK_VERSION
@@ -106,9 +118,11 @@
 endif
 
 ifndef PLATFORM_VERSION_CODENAME
-  # This is the current development code-name, if the build is not a final
-  # release build.  If this is a final release build, it is simply "REL".
-  PLATFORM_VERSION_CODENAME := REL
+  PLATFORM_VERSION_CODENAME := $(PLATFORM_VERSION_CODENAME.$(TARGET_PLATFORM_VERSION))
+  ifndef PLATFORM_VERSION_CODENAME
+    # PLATFORM_VERSION_CODENAME falls back to TARGET_PLATFORM_VERSION
+    PLATFORM_VERSION_CODENAME := $(TARGET_PLATFORM_VERSION)
+  endif
 
   # This is all of the development codenames that are active.  Should be either
   # the same as PLATFORM_VERSION_CODENAME or a comma-separated list of additional