diff --git a/External/build.sh b/External/build.sh
index 8b8f8c8..6505fe8 100755
--- a/External/build.sh
+++ b/External/build.sh
@@ -84,7 +84,7 @@ if [[ $BUILD_PLATFORM != 'Android' ]]; then
             libdecor-0-dev$TARGET_APT_ARCH
     fi
 else
-    if [[ -z $ANDROID_HOME || -z $NDK_VER || -z $PLATFORM_VER || -z $ANDROID_ABI ]]; then
+    if [[ -z $ANDROID_HOME || -z $NDK_VER || -z $ANDROID_ABI ]]; then
         echo "One or more required environment variables are not defined."
         exit 1
     fi
@@ -94,7 +94,7 @@ else
     export ANDROID_NDK_HOME="$ANDROID_HOME/ndk/$NDK_VER"
     export FLAGS="$FLAGS -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK_HOME/build/cmake/android.toolchain.cmake \
                          -DANDROID_HOME=$ANDROID_HOME \
-                         -DANDROID_PLATFORM=$PLATFORM_VER \
+                         -DANDROID_PLATFORM=21 \
                          -DANDROID_ABI=$ANDROID_ABI \
                          -DCMAKE_POSITION_INDEPENDENT_CODE=ON \
                          -DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=BOTH \