diff --git a/build.sh b/build.sh
index 568660bd..9301efa9 100755
--- a/build.sh
+++ b/build.sh
@@ -40,9 +40,27 @@ ROOT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 MONERO_DIR=monero
 MONEROD_EXEC=monerod
 
-# Build libwallet if monero folder doesnt exist
-if [ ! -d $MONERO_DIR/src ]; then 
+# Build libwallet if it doesnt exist
+if [ ! -f $MONERO_DIR/lib/libwallet_merged.a ]; then 
+    echo "libwallet_merged.a not found - Building libwallet"
     $SHELL get_libwallet_api.sh $BUILD_TYPE
+else 
+    source ./$MONERO_DIR/version.sh
+    # update monero submodule
+    git submodule update
+    # compare submodule version with latest build
+    pushd "$MONERO_DIR"
+    get_tag
+    popd
+    echo "latest libwallet version: $GUI_MONERO_VERSION"
+    echo "Installed libwallet version: $VERSIONTAG"
+    # check if recent
+    if [ "$VERSIONTAG" != "$GUI_MONERO_VERSION" ]; then
+        echo "Building new libwallet version $GUI_MONERO_VERSION"
+        $SHELL get_libwallet_api.sh $BUILD_TYPE 
+    else
+        echo "latest libwallet ($GUI_MONERO_VERSION) is already built. Run ./get_libwallet_api.sh to force rebuild"
+    fi
 fi
  
 # build zxcvbn
@@ -73,6 +91,7 @@ pushd "$MONERO_DIR"
 get_tag
 popd
 echo "var GUI_MONERO_VERSION = \"$VERSIONTAG\"" >> version.js
+echo "GUI_MONERO_VERSION=\"$VERSIONTAG\"" >> $MONERO_DIR/version.sh
 
 cd build
 qmake ../monero-wallet-gui.pro "$CONFIG"