diff --git a/python3/Dockerfile b/python3/Dockerfile
index ffcea95670a8e842b7fd2029531f2436d5dc4837..9df4674de4a55e4a9eb46d658d69eea1de6c7dad 100644
--- a/python3/Dockerfile
+++ b/python3/Dockerfile
@@ -8,8 +8,8 @@ FROM ubuntu:18.04
 MAINTAINER xt
 
 COPY sources.list /etc/apt/sources.list
-COPY Python-3.9.0.tar.xz ./python.tar.xz
-COPY Python-3.9.0.tar.xz.asc ./python.tar.xz.asc
+COPY Python-3.6.12.tar.xz ./python.tar.xz
+COPY Python-3.6.12.tar.xz.asc ./python.tar.xz.asc
 COPY get-pip.py ./get-pip.py
 
 # ensure local python is preferred over distribution python
@@ -43,7 +43,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/*
 
 ENV GPG_KEY 0D96DF4D4110E5C43FBFB17F2D347EA6AA65421D
-ENV PYTHON_VERSION 3.9.0
+ENV PYTHON_VERSION 3.6.12
 
 RUN set -ex \
 	\
@@ -85,7 +85,7 @@ RUN cd /usr/local/bin \
 	&& ln -s python3-config python-config
 
 # if this is called "PIP_VERSION", pip explodes with "ValueError: invalid truth value '<VERSION>'"
-ENV PYTHON_PIP_VERSION 20.2.4
+ENV PYTHON_PIP_VERSION 18.0
 
 RUN set -ex; \
 	python get-pip.py \
diff --git a/python3/Python-3.9.0.tar.xz b/python3/Python-3.6.12.tar.xz
similarity index 63%
rename from python3/Python-3.9.0.tar.xz
rename to python3/Python-3.6.12.tar.xz
index dbe002f0b24fac86db30e6dfabfb4ee4597bb0e6..7c78eb2528c7da35f08aa7d7f7b37984acc41ca0 100644
Binary files a/python3/Python-3.9.0.tar.xz and b/python3/Python-3.6.12.tar.xz differ
diff --git a/python3/Python-3.6.12.tar.xz.asc b/python3/Python-3.6.12.tar.xz.asc
new file mode 100644
index 0000000000000000000000000000000000000000..13042ea9a320e8a43a8d0e077840a568219fc63f
--- /dev/null
+++ b/python3/Python-3.6.12.tar.xz.asc
@@ -0,0 +1,16 @@
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diff --git a/python3/Python-3.9.0.tar.xz.asc b/python3/Python-3.9.0.tar.xz.asc
deleted file mode 100644
index c3330fcb2818c89a3b86fac2ca07d2a891033bfe..0000000000000000000000000000000000000000
--- a/python3/Python-3.9.0.tar.xz.asc
+++ /dev/null
@@ -1,16 +0,0 @@
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