5.2.0

• Allow setting token via jupyter_token env (#2921).
• Fix some errors caused by raising 403 in get_current_user (#2919).
• Register contents_manager.files_handler_class directly (#2917).
• Ensure that keyboard shortcuts are disabled when editing them (#2912).
• Make all files in the dashboard editable by default and provide a whitelist of viewable file extensions (#2911).
• The root directory of the notebook server should never be hidden (#2907).
• Fix notebook require config to match tools/build-main (#2888).
• Give page constructor default arguments (#2887).
• Fix codemirror.less to match codemirror's expected padding layout (#2880).
• Add x-xsrftoken to access-control-allow-headers (#2876).
• Buffer messages when websocket connection is interrupted (#2871).
• Load locale dynamically only when not en-us (#2866).
• Changed key strength to 2048 bits (#2861).
• Resync jsversion with python version (#2860).
• Allow copy operation on modified, read-only notebook (#2854).
• Update error handling on apihandlers (#2853).
• Test python 3.6 on travis, drop 3.3 (#2852).
• Avoid base64-literals in image tests (#2851).
• Upgrade xterm.js to 2.9.2 (#2849).
• Changed all python variables named file to file_name to not override built_in file (#2830).
• Add more doc tests (#2823).
• Typos fix (#2815).
• Rename and update license (#2810).
• Travis builds doc (#2808).
• Pull request i18n (#2804).
• Factor out output_prompt_function, as is done with input prompt (#2774).
• Use rfc5987 encoding for filenames (#2767).
• Added path to the resources metadata, the same as in from_filename(...) in nbconvert.exporters.py (#2753).
• Make "extrakeys" consistent for notebook and editor (#2745).
• Bidi support (#2357).

Special thanks to samarsultan and the Arabic Competence and Globalization Center Team at IBM Egypt for adding RTL (right-to-left) support to the notebook!

See the 5.2 milestone on GitHub for a complete list of issues and pull requests involved in this release.