1. Upgrade OkHttp dependency in src/plugin/protocol-okhttp/ivy.xml

2. Upgrade OkHttp's own dependencies in src/plugin/protocol-okhttp/plugin.xml

   To get the list of dependencies and their versions execute in the Nutch root
   folder:
    $ ant clean runtime
    $ ls build/plugins/protocol-okhttp/ \
         | grep '\.jar$' \
         | grep -vF protocol-okhttp.jar \
         | sed 's/^/      <library name="/g' | sed 's/$/"\/>/g'

   In the plugin.xml replace all lines between
      <!-- dependencies of OkHttp -->
   and
      <!-- end of dependencies of OkHttp -->
   with the output of the command above.

3. Build Nutch and run all unit tests:

    $ ant clean runtime test

   At least, run the protocol-okhttp unit tests:

    $ ant test-plugin -Dplugin=protocol-okhttp

4. (optionally but recommended) Run a test crawl using protocol-okhttp