diff --git a/api/Dockerfile b/api/Dockerfile
index 9296785eef25d9b5a14cd9e140b8461ba188eeff..6acdaac56a6fa024917f60ac0629217d93813dc4 100644
--- a/api/Dockerfile
+++ b/api/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.5
+FROM python:3.6
 
 ENV PYTHONUNBUFFERED 1
 
diff --git a/api/docker/Dockerfile.test b/api/docker/Dockerfile.test
index 0990efa512e6a1084249e331e4146f8a223332f5..963e3ab20e4f114a96a176b4a9a1cb5c91f6023c 100644
--- a/api/docker/Dockerfile.test
+++ b/api/docker/Dockerfile.test
@@ -1,4 +1,4 @@
-FROM python:3.5
+FROM python:3.6
 
 ENV PYTHONUNBUFFERED 1
 
diff --git a/changes/changelog.d/121.bugfix b/changes/changelog.d/121.bugfix
new file mode 100644
index 0000000000000000000000000000000000000000..543f5b87b7cbb5bf9155935c266f8bec292c30eb
--- /dev/null
+++ b/changes/changelog.d/121.bugfix
@@ -0,0 +1 @@
+Upgraded to Python 3.6 to fix weird but harmless weakref error on django task (#121)