Zulip server release checklist

This document has reminders of things one might forget to do when preparing a new release.

Upgrade all Python dependencies in requirements to latest upstream versions so they can burn in (use pip list --outdated).
Update all the strings on Transifex and notify translators that they should translate the new strings to get them in for the next release.
Update changelog.md with major changes going into the release.
Create a burndown list of bugs that need to be fixed before we can release, and make sure all of them are being worked on.
Draft the release blog post (aka the release notes.)

Update changelog.md with any changes since the last update, and with revisions from the draft blog post.
Download updated translation strings from Transifex and commit them.
Use build-release-tarball to generate a release tarball.
Test the new tarball extensively, both new install and upgrade from last release, on both Bionic and Focal.
Repeat until release is ready.
When near finished: move the blog post draft to Ghost. (For a draft in Dropbox Paper, use "··· > Download > Markdown" to get a pretty good markup conversion.) Proofread the post, especially for formatting.

Do final updates to changelog.md, for any final changes and with any revisions from the draft blog post. (And the date!)
Update ZULIP_VERSION and LATEST_RELEASE_VERSION in version.py.
For major releases, update API_FEATURE_LEVEL to a feature level for the final release, and document a reserved range.
Use build-release-tarball to generate a final release tarball.
Post the release tarball on https://www.zulip.org/dist/releases/ : add the file, update the zulip-server-latest.tar.gz symlink, and add to SHA256SUMS.txt, using ship-release.sh.
Create a Git tag and push the tag.
Post the release on GitHub, using the text from changelog.md.
Update the Docker image and do a release of that.
Update the image of DigitalOcean one click app using Fabric and publish it to DO marketplace.
Publish the blog post.
Email zulip-announce, post to #announce, and send a tweet.

Push the release commit to master, if applicable (typically for a major release); otherwise, make sure any last changes make it back to master.
Update ZULIP_VERSION in version.py to e.g. 2.2.0+git following a 2.1.0 release, and make a Git tag named e.g. 2.2-dev pointing to this update.
Consider removing a few old releases from ReadTheDocs.