diff --git a/academic/Xyce/Xyce.SlackBuild b/academic/Xyce/Xyce.SlackBuild
index b6390a8af7..c6a139bd2b 100644
--- a/academic/Xyce/Xyce.SlackBuild
+++ b/academic/Xyce/Xyce.SlackBuild
@@ -23,13 +23,12 @@
 #  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 PRGNAM=Xyce
-VERSION=${VERSION:-6.3}
+VERSION=${VERSION:-6.4}
 BUILD=${BUILD:-1}
 TAG=${TAG:-_SBo}
 
 SRCNAM="$PRGNAM"
 
-
 if [ -z "$ARCH" ]; then
   case "$( uname -m )" in
     i?86) ARCH=i486 ;;
@@ -66,14 +65,15 @@ rm -rf $SRCNAM-$VERSION
 tar xvf $CWD/$SRCNAM-$VERSION.tar.gz
 tar xvf $CWD/$SRCNAM\_Docs-$VERSION.tar.gz
 tar xvf $CWD/$SRCNAM\_Regression-$VERSION.tar.gz
+for d in $SRCNAM-$VERSION $SRCNAM\_Docs-$VERSION $SRCNAM\_Regression-$VERSION ; do
+  chown -R root:root $d
+  find -L $d \
+   \( -perm 777 -o -perm 775 -o -perm 750 -o -perm 711 -o -perm 555 \
+    -o -perm 511 \) -exec chmod 755 {} \; -o \
+   \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
+    -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
+done
 cd $SRCNAM-$VERSION
-chown -R root:root .
-find -L . \
- \( -perm 777 -o -perm 775 -o -perm 750 -o -perm 711 -o -perm 555 \
-  -o -perm 511 \) -exec chmod 755 {} \; -o \
- \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
-  -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
-
 
 if [ "${NONFREE:-no}" == yes ]; then
   COPT_DEPS="-DXyce_NONFREE_MODEL=ON"
@@ -88,17 +88,18 @@ else
   COPT_DEPS="$COPTS_DEPS -DXyce_PARALLEL_MPI=OFF"
 fi
 
-mkdir BUILD
-cmake \
-  -DCMAKE_C_FLAGS:STRING="$SLKCFLAGS" \
-  -DCMAKE_CXX_FLAGS:STRING="$SLKCFLAGS" \
-  -DCMAKE_INSTALL_PREFIX=/opt/$PRGNAM \
-  $COPT_DEPS \
-  -DXyce_ENABLE_SHARED=yes \
-  -DCMAKE_BUILD_TYPE=Release
-
-make
-make install DESTDIR=$PKG
+mkdir -p build
+cd build
+  cmake \
+    -DCMAKE_C_FLAGS:STRING="$SLKCFLAGS" \
+    -DCMAKE_CXX_FLAGS:STRING="$SLKCFLAGS -std=c++11 -DXyce_NOX_SIZETYPE" \
+    -DCMAKE_INSTALL_PREFIX=/opt/$PRGNAM \
+    $COPT_DEPS \
+    -DXyce_ENABLE_SHARED=yes \
+    -DCMAKE_BUILD_TYPE=Release ..
+  make
+  make install DESTDIR=$PKG
+cd ..
 
 # Install the test suite manually
 mv $TMP/$PRGNAM\_Regression-$VERSION \
diff --git a/academic/Xyce/Xyce.info b/academic/Xyce/Xyce.info
index 3cb282d97f..8883813222 100644
--- a/academic/Xyce/Xyce.info
+++ b/academic/Xyce/Xyce.info
@@ -1,12 +1,12 @@
 PRGNAM="Xyce"
-VERSION="6.3"
+VERSION="6.4"
 HOMEPAGE="https://xyce.sandia.gov/index.html"
-DOWNLOAD="https://xyce.sandia.gov/downloads/_assets/documents/Xyce-6.3.tar.gz \
- 	  https://xyce.sandia.gov/downloads/_assets/documents/Xyce_Docs-6.3.tar.gz \
-	  https://xyce.sandia.gov/downloads/_assets/documents/Xyce_Regression-6.3.tar.gz"
-MD5SUM="0d390539254cc240967b8df1eee74808 \
- 	7f0cdb4029c3b713af355641f985f4ca \
-	2bdd10c498f134934910d7cc46b81837"
+DOWNLOAD="https://xyce.sandia.gov/downloads/_assets/documents/Xyce-6.4.tar.gz \
+          https://xyce.sandia.gov/downloads/_assets/documents/Xyce_Docs-6.4.tar.gz \
+          https://xyce.sandia.gov/downloads/_assets/documents/Xyce_Regression-6.4.tar.gz"
+MD5SUM="4e80808b72593cdc04ab26b47a0844a1 \
+        f2f3ace727f3bcea7d6881254d730eab \
+        f12df54c999a7bc22b6e8103276fad0e"
 DOWNLOAD_x86_64=""
 MD5SUM_x86_64=""
 REQUIRES="trilinos"