diff --git a/.github/workflows/python-app.yml b/.github/workflows/python-app.yml
index 7a23bb3..7b057d9 100644
--- a/.github/workflows/python-app.yml
+++ b/.github/workflows/python-app.yml
@@ -6,7 +6,7 @@ on: [push, pull_request]
 jobs:
   build:
 
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
 
     steps:
     - uses: actions/checkout@v2
diff --git a/Dockerfile-test b/Dockerfile-test
index df5b881..b1e5340 100644
--- a/Dockerfile-test
+++ b/Dockerfile-test
@@ -1,4 +1,4 @@
-FROM elephant-server:0.4.3
+FROM elephant-server:0.4.4
 
 LABEL maintainer="Ko Sugawara <ko.sugawara@ens-lyon.fr>"
 
diff --git a/Makefile b/Makefile
index 892ac54..0563250 100755
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ help:
 
 ELEPHANT_GPU?=all
 ELEPHANT_WORKSPACE?=${PWD}/workspace
-ELEPHANT_IMAGE_NAME?=elephant-server:0.4.3
+ELEPHANT_IMAGE_NAME?=elephant-server:0.4.4
 ELEPHANT_NVIDIA_GID?=$$(ls -n /dev/nvidia0 2>/dev/null | awk '{print $$4}')
 ELEPHANT_DOCKER?=docker
 
diff --git a/elephant-core/elephant/version.py b/elephant-core/elephant/version.py
index 50ecfe1..035a8e6 100644
--- a/elephant-core/elephant/version.py
+++ b/elephant-core/elephant/version.py
@@ -24,4 +24,4 @@
 # ==============================================================================
 """Version definition."""
 
-__version__ = '0.4.3'
+__version__ = '0.4.4'
diff --git a/elephant_server.ipynb b/elephant_server.ipynb
index 5081149..b1d7b9e 100644
--- a/elephant_server.ipynb
+++ b/elephant_server.ipynb
@@ -51,7 +51,7 @@
         "id": "CpJPKG_ATv39"
       },
       "source": [
-        "%env ELEPHANT_SERVER_VERSION = v0.4.3"
+        "%env ELEPHANT_SERVER_VERSION = v0.4.4"
       ],
       "execution_count": null,
       "outputs": []