diff --git a/repo2docker/buildpacks/conda/environment.frozen.yml b/repo2docker/buildpacks/conda/environment.frozen.yml
index 146d7ef5..a8af6656 100644
--- a/repo2docker/buildpacks/conda/environment.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.frozen.yml
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM environment.py-3.6.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-09-06 21:22:43 UTC
+# Frozen on 2018-09-07 15:57:59 UTC
 name: r2d
 channels:
   - conda-forge
@@ -20,6 +20,7 @@ dependencies:
   - cryptography=2.3.1=py36hdffb7b8_0
   - cryptography-vectors=2.3.1=py36_0
   - decorator=4.3.0=py_0
+  - defusedxml=0.5.0=py36_0
   - entrypoints=0.2.3=py36_2
   - gmp=6.1.2=hfc679d8_0
   - html5lib=1.0.1=py_0
@@ -39,11 +40,11 @@ dependencies:
   - jupyterlab_launcher=0.13.1=py_2
   - libffi=3.2.1=hfc679d8_5
   - libgcc-ng=7.2.0=hdf63c60_3
-  - libsodium=1.0.16=0
+  - libsodium=1.0.16=h470a237_1
   - libstdcxx-ng=7.2.0=hdf63c60_3
   - markupsafe=1.0=py36h470a237_1
   - mistune=0.8.3=py36h470a237_2
-  - nbconvert=5.3.1=py_1
+  - nbconvert=5.4.0=0
   - nbformat=4.4.0=py_1
   - ncurses=6.1=hfc679d8_1
   - notebook=5.6.0=py36_1
@@ -87,5 +88,7 @@ dependencies:
   - zeromq=4.2.5=hfc679d8_5
   - zlib=1.2.11=h470a237_3
   - zope.interface=4.5.0=py36h470a237_1
+  - pip:
+    - nteract-on-jupyter==1.9.6
 prefix: /opt/conda/envs/r2d
 
diff --git a/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml b/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
index ba65a59f..96353810 100644
--- a/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.py-2.7.frozen.yml
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM environment.py-2.7.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-09-06 21:13:00 UTC
+# Frozen on 2018-09-07 15:49:13 UTC
 name: r2d
 channels:
   - conda-forge
@@ -20,7 +20,7 @@ dependencies:
   - jupyter_client=5.2.3=py_1
   - jupyter_core=4.4.0=py_0
   - libgcc-ng=7.2.0=hdf63c60_3
-  - libsodium=1.0.16=0
+  - libsodium=1.0.16=h470a237_1
   - libstdcxx-ng=7.2.0=hdf63c60_3
   - ncurses=6.1=hfc679d8_1
   - openssl=1.0.2p=h470a237_0
@@ -49,5 +49,7 @@ dependencies:
   - wheel=0.31.1=py27_1
   - zeromq=4.2.5=hfc679d8_5
   - zlib=1.2.11=h470a237_3
+  - pip:
+    - backports.ssl-match-hostname==3.5.0.1
 prefix: /opt/conda/envs/r2d
 
diff --git a/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml b/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
index ff2454fd..9e613deb 100644
--- a/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.py-3.5.frozen.yml
@@ -1,91 +1,9 @@
 # AUTO GENERATED FROM environment.py-3.5.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-09-06 21:16:33 UTC
+# Frozen on 2018-09-07 15:52:23 UTC
 name: r2d
 channels:
   - conda-forge
   - defaults
   - conda-forge/label/broken
-dependencies:
-  - appdirs=1.4.3=py_1
-  - asn1crypto=0.24.0=py35_3
-  - attrs=18.2.0=py_0
-  - automat=0.7.0=py_1
-  - backcall=0.1.0=py_0
-  - bleach=2.1.4=py_1
-  - bzip2=1.0.6=h470a237_2
-  - ca-certificates=2018.8.24=ha4d7672_0
-  - certifi=2018.8.24=py35_1
-  - cffi=1.11.5=py35h5e8e0c9_1
-  - constantly=15.1.0=py_0
-  - cryptography=2.3.1=py35hdffb7b8_0
-  - cryptography-vectors=2.3.1=py35_0
-  - decorator=4.3.0=py_0
-  - entrypoints=0.2.3=py35_2
-  - gmp=6.1.2=hfc679d8_0
-  - html5lib=1.0.1=py_0
-  - hyperlink=17.3.1=py_0
-  - idna=2.7=py35_2
-  - incremental=17.5.0=py_0
-  - ipykernel=4.9.0=py35_0
-  - ipython=6.5.0=py35_0
-  - ipython_genutils=0.2.0=py_1
-  - ipywidgets=7.2.1=py35_1
-  - jedi=0.12.1=py35_0
-  - jinja2=2.10=py_1
-  - jsonschema=2.6.0=py35_2
-  - jupyter_client=5.2.3=py_1
-  - jupyter_core=4.4.0=py_0
-  - jupyterlab=0.34.0=py35_0
-  - jupyterlab_launcher=0.13.1=py_2
-  - libffi=3.2.1=hfc679d8_5
-  - libgcc-ng=7.2.0=hdf63c60_3
-  - libsodium=1.0.16=0
-  - libstdcxx-ng=7.2.0=hdf63c60_3
-  - markupsafe=1.0=py35h470a237_1
-  - mistune=0.8.3=py35h470a237_2
-  - nbconvert=5.3.1=py_1
-  - nbformat=4.4.0=py_1
-  - ncurses=6.1=hfc679d8_1
-  - notebook=5.6.0=py35_1
-  - openssl=1.0.2p=h470a237_0
-  - pandoc=2.2.2=1
-  - pandocfilters=1.4.2=py_1
-  - parso=0.3.1=py_0
-  - pexpect=4.6.0=py35_0
-  - pickleshare=0.7.4=py35_0
-  - pip=18.0=py35_1
-  - prometheus_client=0.3.0=py_0
-  - prompt_toolkit=1.0.15=py_1
-  - ptyprocess=0.6.0=py35_0
-  - pyasn1=0.4.4=py_0
-  - pyasn1-modules=0.2.1=py_0
-  - pycparser=2.18=py_1
-  - pygments=2.2.0=py_1
-  - pyhamcrest=1.9.0=py_2
-  - pyopenssl=18.0.0=py35_0
-  - python=3.5.5=h5001a0f_2
-  - python-dateutil=2.7.3=py_0
-  - pyzmq=17.1.2=py35hae99301_0
-  - readline=7.0=haf1bffa_1
-  - send2trash=1.5.0=py_0
-  - service_identity=17.0.0=py_0
-  - setuptools=40.2.0=py35_0
-  - simplegeneric=0.8.1=py_1
-  - six=1.11.0=py35_1
-  - sqlite=3.24.0=h2f33b56_1
-  - terminado=0.8.1=py35_1
-  - testpath=0.3.1=py35_1
-  - tk=8.6.8=0
-  - tornado=4.5.3=py35_0
-  - traitlets=4.3.2=py35_0
-  - twisted=18.7.0=py35h470a237_1
-  - wcwidth=0.1.7=py_1
-  - webencodings=0.5.1=py_1
-  - wheel=0.31.1=py35_1
-  - widgetsnbextension=3.2.1=py35_1
-  - xz=5.2.4=h470a237_1
-  - zeromq=4.2.5=hfc679d8_5
-  - zlib=1.2.11=h470a237_3
-  - zope.interface=4.5.0=py35h470a237_1
 prefix: /opt/conda/envs/r2d
 
diff --git a/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml b/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
index 146d7ef5..a8af6656 100644
--- a/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
+++ b/repo2docker/buildpacks/conda/environment.py-3.6.frozen.yml
@@ -1,5 +1,5 @@
 # AUTO GENERATED FROM environment.py-3.6.yml, DO NOT MANUALLY MODIFY
-# Frozen on 2018-09-06 21:22:43 UTC
+# Frozen on 2018-09-07 15:57:59 UTC
 name: r2d
 channels:
   - conda-forge
@@ -20,6 +20,7 @@ dependencies:
   - cryptography=2.3.1=py36hdffb7b8_0
   - cryptography-vectors=2.3.1=py36_0
   - decorator=4.3.0=py_0
+  - defusedxml=0.5.0=py36_0
   - entrypoints=0.2.3=py36_2
   - gmp=6.1.2=hfc679d8_0
   - html5lib=1.0.1=py_0
@@ -39,11 +40,11 @@ dependencies:
   - jupyterlab_launcher=0.13.1=py_2
   - libffi=3.2.1=hfc679d8_5
   - libgcc-ng=7.2.0=hdf63c60_3
-  - libsodium=1.0.16=0
+  - libsodium=1.0.16=h470a237_1
   - libstdcxx-ng=7.2.0=hdf63c60_3
   - markupsafe=1.0=py36h470a237_1
   - mistune=0.8.3=py36h470a237_2
-  - nbconvert=5.3.1=py_1
+  - nbconvert=5.4.0=0
   - nbformat=4.4.0=py_1
   - ncurses=6.1=hfc679d8_1
   - notebook=5.6.0=py36_1
@@ -87,5 +88,7 @@ dependencies:
   - zeromq=4.2.5=hfc679d8_5
   - zlib=1.2.11=h470a237_3
   - zope.interface=4.5.0=py36h470a237_1
+  - pip:
+    - nteract-on-jupyter==1.9.6
 prefix: /opt/conda/envs/r2d
 
diff --git a/repo2docker/buildpacks/conda/freeze.py b/repo2docker/buildpacks/conda/freeze.py
index b4be9a7d..4e37bd81 100755
--- a/repo2docker/buildpacks/conda/freeze.py
+++ b/repo2docker/buildpacks/conda/freeze.py
@@ -19,7 +19,10 @@ import sys
 from ruamel.yaml import YAML
 
 
-MINICONDA_VERSION = '4.5.11'
+# Docker image version can be different than conda version,
+# since miniconda3 docker images seem to lag conda releases.
+MINICONDA_DOCKER_VERSION = '4.5.4'
+CONDA_VERSION = '4.5.11'
 
 HERE = pathlib.Path(os.path.dirname(os.path.abspath(__file__)))
 
@@ -54,10 +57,10 @@ def freeze(env_file, frozen_file):
         '--rm',
         '-v' f"{HERE}:/r2d",
         '-it',
-        f"continuumio/miniconda3:{MINICONDA_VERSION}",
+        f"continuumio/miniconda3:{MINICONDA_DOCKER_VERSION}",
         "sh", "-c",
         '; '.join([
-            # f"conda install -yq conda={CONDA_VERSION}",
+            f"conda install -yq conda={CONDA_VERSION}",
             'conda config --add channels conda-forge',
             'conda config --system --set auto_update_conda false',
             f"conda env create -v -f /r2d/{env_file} -n r2d",