title: Updating a Conda environment only through conda-forge channel
body: <p>I have Miniconda installed with 2 environments:  <strong>base</strong> and <em>gis</em>. Packages in <strong>gis</strong> were installed from <em>coda-forge</em>. I have 2 questions:</p>
  
  <p>Q1)   want to update all packages in <strong>gis</strong> environment only from <em>conda-forge</em>. Am I using correct command ?</p>
  
  <p>Q2) Why it is downgrading numpy-base ?  It is updating other packages and when  <em>conda-forge</em> still has several newer versions of 1.15.3 of numpy-base, why it is being downgraded ? </p>
  
  <blockquote>
    <p>(gis) [arnuld@arch64 ~]$ conda update --all -c conda-forge<br>
    Solving environment: done</p>
    
    <h2>Package Plan</h2>
    
    <p>environment location: /home/arnuld/.local/miniconda/envs/gis</p>
    
    <p>The following packages will be downloaded:</p>
  
  <pre><code>package                    |            build
  ---------------------------|-----------------
  matplotlib-3.0.1           |       h8a2030e_1           6 KB  conda-forge
  openblas-0.3.3             |       ha44fe06_1        13.7 MB  conda-forge
  libopenblas-0.2.20         |       h9ac9557_7         8.8 MB
  numpy-base-1.14.3          |   py36h0ea5e3f_1         4.1 MB
  blas-1.1                   |         openblas           1 KB  conda-forge
  krb5-1.16.2                |       hbb41f41_0         1.4 MB  conda-forge
  scipy-1.1.0                |py36_blas_openblashb06ca3d_202        39.8 MB  conda-forge
  mkl_random-1.0.2           |           py36_0         1.3 MB  conda-forge
  numpy-1.15.3               |py36_blas_openblashb06ca3d_0         9.4 MB  conda-forge
  matplotlib-base-3.0.1      |   py36hc039c98_1         9.2 MB  conda-forge
  ------------------------------------------------------------
                                         Total:        87.6 MB
  </code></pre>
    
    <p>The following NEW packages will be INSTALLED:</p>
  
  <pre><code>libopenblas:     0.2.20-h9ac9557_7                
  matplotlib-base: 3.0.1-py36hc039c98_1  conda-forge
  openblas:        0.3.3-ha44fe06_1      conda-forge
  </code></pre>
    
    <p>The following packages will be UPDATED:</p>
  
  <pre><code>blas:            1.0-mkl                           --&gt; 1.1-openblas                         conda-forge
  krb5:            1.16.1-hbb41f41_0     conda-forge --&gt; 1.16.2-hbb41f41_0                    conda-forge
  matplotlib:      2.2.3-py36h8e2386c_0  conda-forge --&gt; 3.0.1-h8a2030e_1                     conda-forge
  mkl_random:      1.0.1-py36_0          conda-forge --&gt; 1.0.2-py36_0                         conda-forge
  numpy:           1.15.0-py36h1b885b7_0             --&gt; 1.15.3-py36_blas_openblashb06ca3d_0  conda-forge [blas_openblas]
  scipy:           1.1.0-py36hc49cb51_0              --&gt; 1.1.0-py36_blas_openblashb06ca3d_202 conda-forge [blas_openblas]
  </code></pre>
    
    <p>The following packages will be DOWNGRADED:</p>
  
  <pre><code>numpy-base:      1.15.0-py36h3dfced4_0             --&gt; 1.14.3-py36h0ea5e3f_1                           
  </code></pre>
    
    <p>Proceed ([y]/n)? n</p>
  </blockquote>
  
  <pre><code>[arnuld@arch64 ~]$ conda list -n gis
  # packages in environment at /home/arnuld/.local/miniconda/envs/gis:
  #
  # Name                    Version                   Build  Channel
  attrs                     18.2.0                     py_0    conda-forge
  backcall                  0.1.0                      py_0    conda-forge
  blas                      1.0                         mkl  
  bleach                    3.0.2                      py_0    conda-forge
  boost-cpp                 1.67.0               h3a22d5f_0    conda-forge
  bzip2                     1.0.6                h470a237_2    conda-forge
  ca-certificates           2018.10.15           ha4d7672_0    conda-forge
  cairo                     1.14.12              he6fea26_5    conda-forge
  certifi                   2018.10.15            py36_1000    conda-forge
  click                     7.0                        py_0    conda-forge
  click-plugins             1.0.4                      py_0    conda-forge
  cligj                     0.5.0                      py_0    conda-forge
  curl                      7.62.0               h74213dd_0    conda-forge
  cycler                    0.10.0                     py_1    conda-forge
  dbus                      1.13.0               h3a4f0e9_0    conda-forge
  decorator                 4.3.0                      py_0    conda-forge
  descartes                 1.1.0                      py_2    conda-forge
  entrypoints               0.2.3                 py36_1002    conda-forge
  expat                     2.2.5                hfc679d8_2    conda-forge
  fiona                     1.8.0            py36hfc77a4a_0    conda-forge
  fontconfig                2.13.1               h65d0f4c_0    conda-forge
  freetype                  2.9.1                h6debe1e_4    conda-forge
  freexl                    1.0.5                h470a237_2    conda-forge
  gdal                      2.3.2            py36hb00a9d7_0    conda-forge
  geopandas                 0.4.0                      py_1    conda-forge
  geos                      3.6.2                hfc679d8_3    conda-forge
  geotiff                   1.4.2                h700e5ad_5    conda-forge
  gettext                   0.19.8.1             h5e8e0c9_1    conda-forge
  giflib                    5.1.4                h470a237_1    conda-forge
  glib                      2.55.0               h464dc38_2    conda-forge
  gmp                       6.1.2                hfc679d8_0    conda-forge
  gst-plugins-base          1.12.5               hde13a9d_0    conda-forge
  gstreamer                 1.12.5               h61a6719_0    conda-forge
  hdf4                      4.2.13               h951d187_2    conda-forge
  hdf5                      1.10.3               hc401514_2    conda-forge
  icu                       58.2                 hfc679d8_0    conda-forge
  intel-openmp              2019.0                      118  
  ipykernel                 5.1.0              pyh24bf2e0_0    conda-forge
  ipython                   7.1.1           py36h24bf2e0_1000    conda-forge
  ipython_genutils          0.2.0                      py_1    conda-forge
  jedi                      0.13.1                py36_1000    conda-forge
  jinja2                    2.10                       py_1    conda-forge
  jpeg                      9c                   h470a237_1    conda-forge
  json-c                    0.12.1               h470a237_1    conda-forge
  jsonschema                3.0.0a3               py36_1000    conda-forge
  jupyter_client            5.2.3                      py_1    conda-forge
  jupyter_core              4.4.0                      py_0    conda-forge
  kealib                    1.4.10               hb88cf67_0    conda-forge
  kiwisolver                1.0.1            py36h2d50403_2    conda-forge
  krb5                      1.16.1               hbb41f41_0    conda-forge
  libcurl                   7.62.0               hbdb9355_0    conda-forge
  libdap4                   3.19.1               h8fe5423_1    conda-forge
  libedit                   3.1.20170329         haf1bffa_1    conda-forge
  libffi                    3.2.1                hfc679d8_5    conda-forge
  libgcc-ng                 7.2.0                hdf63c60_3    conda-forge
  libgdal                   2.3.2                hc73897a_0    conda-forge
  libgfortran               3.0.0                         1    conda-forge
  libgfortran-ng            7.2.0                hdf63c60_3    conda-forge
  libiconv                  1.15                 h470a237_3    conda-forge
  libkml                    1.3.0                hccc92b1_8    conda-forge
  libnetcdf                 4.6.1               h9cd6fdc_11    conda-forge
  libpng                    1.6.35               ha92aebf_2    conda-forge
  libpq                     10.5                 he29860b_0    conda-forge
  libsodium                 1.0.16               h470a237_1    conda-forge
  libspatialindex           1.8.5                hfc679d8_3    conda-forge
  libspatialite             4.3.0a              hdfcc80b_23    conda-forge
  libssh2                   1.8.0                h5b517e9_2    conda-forge
  libstdcxx-ng              7.2.0                hdf63c60_3    conda-forge
  libtiff                   4.0.9                he6b73bb_2    conda-forge
  libuuid                   2.32.1               h470a237_2    conda-forge
  libxcb                    1.13                 h470a237_2    conda-forge
  libxml2                   2.9.8                h422b904_5    conda-forge
  markupsafe                1.0              py36h470a237_1    conda-forge
  matplotlib                2.2.3            py36h8e2386c_0    conda-forge
  mistune                   0.8.4            py36h470a237_0    conda-forge
  mkl                       2019.0                      118  
  mkl_fft                   1.0.6                    py36_0    conda-forge
  mkl_random                1.0.1                    py36_0    conda-forge
  munch                     2.3.2                      py_0    conda-forge
  nbconvert                 5.3.1                      py_1    conda-forge
  nbformat                  4.4.0                      py_1    conda-forge
  ncurses                   6.1                  hfc679d8_1    conda-forge
  notebook                  5.7.0                 py36_1000    conda-forge
  numpy                     1.15.0           py36h1b885b7_0  
  numpy-base                1.15.0           py36h3dfced4_0  
  openjpeg                  2.3.0                h0e734dc_3    conda-forge
  openssl                   1.0.2p               h470a237_1    conda-forge
  pandas                    0.23.4           py36hf8a1672_0    conda-forge
  pandoc                    2.3.1                         0    conda-forge
  pandocfilters             1.4.2                      py_1    conda-forge
  parso                     0.3.1                      py_0    conda-forge
  pcre                      8.41                 hfc679d8_3    conda-forge
  pexpect                   4.6.0                 py36_1000    conda-forge
  pickleshare               0.7.5                 py36_1000    conda-forge
  pip                       18.1                  py36_1000    conda-forge
  pixman                    0.34.0               h470a237_3    conda-forge
  poppler                   0.67.0               h4d7e492_3    conda-forge
  poppler-data              0.4.9                         0    conda-forge
  postgresql                10.5                 h66035e0_0    conda-forge
  proj4                     4.9.3                h470a237_8    conda-forge
  prometheus_client         0.4.2                      py_0    conda-forge
  prompt_toolkit            2.0.7                      py_0    conda-forge
  psycopg2                  2.7.5            py36hdffb7b8_2    conda-forge
  pthread-stubs             0.4                  h470a237_1    conda-forge
  ptyprocess                0.6.0                 py36_1000    conda-forge
  pygments                  2.2.0                      py_1    conda-forge
  pyparsing                 2.3.0                      py_0    conda-forge
  pyproj                    1.9.5.1          py36h508ed2a_6    conda-forge
  pyqt                      5.6.0            py36h8210e8a_7    conda-forge
  pyrsistent                0.14.5           py36h470a237_1    conda-forge
  pysal                     1.14.4.post2          py36_1001    conda-forge
  python                    3.6.6                h5001a0f_3    conda-forge
  python-dateutil           2.7.5                      py_0    conda-forge
  pytz                      2018.7                     py_0    conda-forge
  pyzmq                     17.1.2           py36hae99301_1    conda-forge
  qt                        5.6.2                hf70d934_9    conda-forge
  readline                  7.0                  haf1bffa_1    conda-forge
  rtree                     0.8.3                 py36_1000    conda-forge
  scipy                     1.1.0            py36hc49cb51_0  
  send2trash                1.5.0                      py_0    conda-forge
  setuptools                40.5.0                   py36_0    conda-forge
  shapely                   1.6.4            py36h164cb2d_1    conda-forge
  sip                       4.18.1           py36hfc679d8_0    conda-forge
  six                       1.11.0                py36_1001    conda-forge
  sqlalchemy                1.2.13           py36h470a237_0    conda-forge
  sqlite                    3.25.2               hb1c47c0_0    conda-forge
  terminado                 0.8.1                 py36_1001    conda-forge
  testpath                  0.4.2                 py36_1000    conda-forge
  tk                        8.6.8                ha92aebf_0    conda-forge
  tornado                   5.1.1            py36h470a237_0    conda-forge
  traitlets                 4.3.2                 py36_1000    conda-forge
  wcwidth                   0.1.7                      py_1    conda-forge
  webencodings              0.5.1                      py_1    conda-forge
  wheel                     0.32.2                   py36_0    conda-forge
  xerces-c                  3.2.0                h5d6a6da_2    conda-forge
  xorg-kbproto              1.0.7                h470a237_2    conda-forge
  xorg-libice               1.0.9                h470a237_4    conda-forge
  xorg-libsm                1.2.3                h8c8a85c_0    conda-forge
  xorg-libx11               1.6.6                h470a237_0    conda-forge
  xorg-libxau               1.0.8                h470a237_6    conda-forge
  xorg-libxdmcp             1.1.2                h470a237_7    conda-forge
  xorg-libxext              1.3.3                h470a237_4    conda-forge
  xorg-libxrender           0.9.10               h470a237_2    conda-forge
  xorg-renderproto          0.11.1               h470a237_2    conda-forge
  xorg-xextproto            7.3.0                h470a237_2    conda-forge
  xorg-xproto               7.0.31               h470a237_7    conda-forge
  xz                        5.2.4                h470a237_1    conda-forge
  zeromq                    4.2.5                hfc679d8_6    conda-forge
  zlib                      1.2.11               h470a237_3    conda-forge
  [arnuld@arch64 ~]$ 
  </code></pre>