diff --git a/2.7/Dockerfile b/2.7/Dockerfile
index 2ca772a3a..e56901f64 100644
--- a/2.7/Dockerfile
+++ b/2.7/Dockerfile
@@ -47,7 +47,12 @@ RUN set -ex \
 		&& wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
 		&& python2 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
-	&& pip install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/2.7/alpine/Dockerfile b/2.7/alpine/Dockerfile
index 302efeec8..2c53d0cb1 100644
--- a/2.7/alpine/Dockerfile
+++ b/2.7/alpine/Dockerfile
@@ -64,7 +64,12 @@ RUN set -ex \
 		&& wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
 		&& python2 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
-	&& pip install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/2.7/slim/Dockerfile b/2.7/slim/Dockerfile
index 11a392283..6e656bc22 100644
--- a/2.7/slim/Dockerfile
+++ b/2.7/slim/Dockerfile
@@ -60,7 +60,12 @@ RUN set -ex \
 		&& wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
 		&& python2 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
-	&& pip install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/2.7/wheezy/Dockerfile b/2.7/wheezy/Dockerfile
index ac5182b09..6c3b68436 100644
--- a/2.7/wheezy/Dockerfile
+++ b/2.7/wheezy/Dockerfile
@@ -47,7 +47,12 @@ RUN set -ex \
 		&& wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
 		&& python2 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
-	&& pip install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.3/Dockerfile b/3.3/Dockerfile
index c9784367b..ee3062605 100644
--- a/3.3/Dockerfile
+++ b/3.3/Dockerfile
@@ -56,7 +56,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.3/alpine/Dockerfile b/3.3/alpine/Dockerfile
index b04660e17..a4af10164 100644
--- a/3.3/alpine/Dockerfile
+++ b/3.3/alpine/Dockerfile
@@ -73,7 +73,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.3/slim/Dockerfile b/3.3/slim/Dockerfile
index a12e09c9e..847fc3c85 100644
--- a/3.3/slim/Dockerfile
+++ b/3.3/slim/Dockerfile
@@ -69,7 +69,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.3/wheezy/Dockerfile b/3.3/wheezy/Dockerfile
index ef0c41598..46980f537 100644
--- a/3.3/wheezy/Dockerfile
+++ b/3.3/wheezy/Dockerfile
@@ -56,7 +56,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.4/Dockerfile b/3.4/Dockerfile
index c42717bf3..9fa0f7076 100644
--- a/3.4/Dockerfile
+++ b/3.4/Dockerfile
@@ -56,7 +56,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.4/alpine/Dockerfile b/3.4/alpine/Dockerfile
index 19dc70c98..b6c90b564 100644
--- a/3.4/alpine/Dockerfile
+++ b/3.4/alpine/Dockerfile
@@ -73,7 +73,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.4/slim/Dockerfile b/3.4/slim/Dockerfile
index 89699fd6f..4ef2a4d96 100644
--- a/3.4/slim/Dockerfile
+++ b/3.4/slim/Dockerfile
@@ -69,7 +69,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.4/wheezy/Dockerfile b/3.4/wheezy/Dockerfile
index 72eb6bddf..73d1c235d 100644
--- a/3.4/wheezy/Dockerfile
+++ b/3.4/wheezy/Dockerfile
@@ -56,7 +56,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.5/Dockerfile b/3.5/Dockerfile
index b9aa4ce0c..69d91321e 100644
--- a/3.5/Dockerfile
+++ b/3.5/Dockerfile
@@ -56,7 +56,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.5/alpine/Dockerfile b/3.5/alpine/Dockerfile
index d368cbb8c..bc2c41f2b 100644
--- a/3.5/alpine/Dockerfile
+++ b/3.5/alpine/Dockerfile
@@ -73,7 +73,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.5/slim/Dockerfile b/3.5/slim/Dockerfile
index d981a6a1e..111ff9711 100644
--- a/3.5/slim/Dockerfile
+++ b/3.5/slim/Dockerfile
@@ -69,7 +69,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.5/windows/windowsservercore/Dockerfile b/3.5/windows/windowsservercore/Dockerfile
index 917dfb075..64c018734 100644
--- a/3.5/windows/windowsservercore/Dockerfile
+++ b/3.5/windows/windowsservercore/Dockerfile
@@ -42,7 +42,10 @@ RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env
 	\
 	$pipInstall = ('pip=={0}' -f $env:PYTHON_PIP_VERSION); \
 	Write-Host ('Installing {0} ...' -f $pipInstall); \
-	pip install --no-cache-dir --upgrade $pipInstall; \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	pip install --no-cache-dir --upgrade --force-reinstall $pipInstall; \
 	\
 	Write-Host 'Verifying pip install ...'; \
 	pip --version; \
diff --git a/3.6/Dockerfile b/3.6/Dockerfile
index fff6d7720..5e703d27e 100644
--- a/3.6/Dockerfile
+++ b/3.6/Dockerfile
@@ -14,7 +14,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/*
 
 ENV GPG_KEY 0D96DF4D4110E5C43FBFB17F2D347EA6AA65421D
-ENV PYTHON_VERSION 3.6.0a3
+ENV PYTHON_VERSION 3.6.0a4
 
 # if this is called "PIP_VERSION", pip explodes with "ValueError: invalid truth value '<VERSION>'"
 ENV PYTHON_PIP_VERSION 8.1.2
@@ -50,7 +50,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.6/alpine/Dockerfile b/3.6/alpine/Dockerfile
index 96bedb99e..4c014f49d 100644
--- a/3.6/alpine/Dockerfile
+++ b/3.6/alpine/Dockerfile
@@ -12,7 +12,7 @@ ENV LANG C.UTF-8
 RUN apk add --no-cache ca-certificates
 
 ENV GPG_KEY 0D96DF4D4110E5C43FBFB17F2D347EA6AA65421D
-ENV PYTHON_VERSION 3.6.0a3
+ENV PYTHON_VERSION 3.6.0a4
 
 # if this is called "PIP_VERSION", pip explodes with "ValueError: invalid truth value '<VERSION>'"
 ENV PYTHON_PIP_VERSION 8.1.2
@@ -67,7 +67,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.6/slim/Dockerfile b/3.6/slim/Dockerfile
index 75dbc9136..ab7ade544 100644
--- a/3.6/slim/Dockerfile
+++ b/3.6/slim/Dockerfile
@@ -15,7 +15,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 	&& rm -rf /var/lib/apt/lists/*
 
 ENV GPG_KEY 0D96DF4D4110E5C43FBFB17F2D347EA6AA65421D
-ENV PYTHON_VERSION 3.6.0a3
+ENV PYTHON_VERSION 3.6.0a4
 
 # if this is called "PIP_VERSION", pip explodes with "ValueError: invalid truth value '<VERSION>'"
 ENV PYTHON_PIP_VERSION 8.1.2
@@ -63,7 +63,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/3.6/windows/windowsservercore/Dockerfile b/3.6/windows/windowsservercore/Dockerfile
index ec45dc550..b5fa44ea5 100644
--- a/3.6/windows/windowsservercore/Dockerfile
+++ b/3.6/windows/windowsservercore/Dockerfile
@@ -2,7 +2,7 @@ FROM microsoft/windowsservercore
 
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop';"]
 
-ENV PYTHON_VERSION 3.6.0a3
+ENV PYTHON_VERSION 3.6.0a4
 ENV PYTHON_RELEASE 3.6.0
 
 # if this is called "PIP_VERSION", pip explodes with "ValueError: invalid truth value '<VERSION>'"
@@ -36,7 +36,10 @@ RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env
 	\
 	$pipInstall = ('pip=={0}' -f $env:PYTHON_PIP_VERSION); \
 	Write-Host ('Installing {0} ...' -f $pipInstall); \
-	pip install --no-cache-dir --upgrade $pipInstall; \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	pip install --no-cache-dir --upgrade --force-reinstall $pipInstall; \
 	\
 	Write-Host 'Verifying pip install ...'; \
 	pip --version; \
diff --git a/Dockerfile-alpine.template b/Dockerfile-alpine.template
index 22a7bae0e..5a9a60e07 100644
--- a/Dockerfile-alpine.template
+++ b/Dockerfile-alpine.template
@@ -67,7 +67,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/Dockerfile-debian.template b/Dockerfile-debian.template
index f9df74b38..56c6ef26d 100644
--- a/Dockerfile-debian.template
+++ b/Dockerfile-debian.template
@@ -50,7 +50,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/Dockerfile-slim.template b/Dockerfile-slim.template
index c0ac7258c..1eb9bb10c 100644
--- a/Dockerfile-slim.template
+++ b/Dockerfile-slim.template
@@ -63,7 +63,12 @@ RUN set -ex \
 		&& python3 /tmp/get-pip.py "pip==$PYTHON_PIP_VERSION" \
 		&& rm /tmp/get-pip.py \
 	; fi \
-	&& pip3 install --no-cache-dir --upgrade "pip==$PYTHON_PIP_VERSION" \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	&& pip3 install --no-cache-dir --upgrade --force-reinstall "pip==$PYTHON_PIP_VERSION" \
+# then we use "pip list" to ensure we don't have more than one pip version installed
+# https://github.com/docker-library/python/pull/100
 	&& [ "$(pip list |tac|tac| awk -F '[ ()]+' '$1 == "pip" { print $2; exit }')" = "$PYTHON_PIP_VERSION" ] \
 	\
 	&& find /usr/local -depth \
diff --git a/Dockerfile-windowsservercore.template b/Dockerfile-windowsservercore.template
index d74d0f9c7..01d1a8c36 100644
--- a/Dockerfile-windowsservercore.template
+++ b/Dockerfile-windowsservercore.template
@@ -36,7 +36,10 @@ RUN $url = ('https://www.python.org/ftp/python/{0}/python-{1}-amd64.exe' -f $env
 	\
 	$pipInstall = ('pip=={0}' -f $env:PYTHON_PIP_VERSION); \
 	Write-Host ('Installing {0} ...' -f $pipInstall); \
-	pip install --no-cache-dir --upgrade $pipInstall; \
+# we use "--force-reinstall" for the case where the version of pip we're trying to install is the same as the version bundled with Python
+# ("Requirement already up-to-date: pip==8.1.2 in /usr/local/lib/python3.6/site-packages")
+# https://github.com/docker-library/python/pull/143#issuecomment-241032683
+	pip install --no-cache-dir --upgrade --force-reinstall $pipInstall; \
 	\
 	Write-Host 'Verifying pip install ...'; \
 	pip --version; \