diff --git a/README.md b/README.md
index be1cdb760759680871f307d425f2e11f716b6165..0d1f67226cdd58822777327dbc016a867dfff99f 100644
--- a/README.md
+++ b/README.md
@@ -15,9 +15,9 @@ cd eic_container
    modeuefile will be installed to `$PREFIX/../../etc/modulefiles`. 
    You can use the `-v` flag to select the version you want to deploy, or omit the 
    flag if you want to install the master build. The recommended stable 
-   release version is `v2.3.0`.
+   release version is `v2.3.1`.
 ```bash
-./deploy.py -v 2.3.0 <PREFIX>
+./deploy.py -v 2.3.1 <PREFIX>
 ```
 
    Available flags:
diff --git a/VERSION b/VERSION
index 276cbf9e2858c779297bb9f73b34170302949ec4..2bf1c1ccf363acd53eaf92ef33a7f11f5f4557c2 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.3.0
+2.3.1
diff --git a/containers/release/Dockerfile.in b/containers/release/Dockerfile.in
index 3696ffc4bddce643b40ceea4c2f761256d04f9e8..cb21cf8d47ba2b41760752d3ca1fe0bcb2de8cd2 100644
--- a/containers/release/Dockerfile.in
+++ b/containers/release/Dockerfile.in
@@ -35,6 +35,7 @@ RUN apt-get -yqq update \
         ghostscript \
         gv \
         poppler-utils \
+        parallel \
  && apt-get -yqq autoremove \
  && rm -rf /var/lib/apt/lists/*