fix version number for older security features

Change-Id: I7a9e0ab6430ced37e2662d8252bfa184958cb2ff
diff --git a/src/tech/security/index.md b/src/tech/security/index.md
index b384546..68e65af 100644
--- a/src/tech/security/index.md
+++ b/src/tech/security/index.md
@@ -319,7 +319,7 @@
 exploit. The Android SDK, compilers, and OS use tools to make common memory
 corruption issues significantly harder to exploit, including:
 
-**Android 2.2+**
+**Android 1.5+**
 
 + ProPolice to prevent stack buffer overruns (-fstack-protector)
 + safe_iop to reduce integer overflows