diff --git a/api/Dockerfile b/api/Dockerfile
index 9296785ee..6acdaac56 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 0990efa51..963e3ab20 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 000000000..543f5b87b
--- /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)