Major changes

• Upgrade the base system to the Debian Stretch 9.2 point-release
  which gives us tons of bugfixes (Closes: #14714).

• Install Linux 4.13.0-1 (Closes: #14789).

• Security fixes

• Upgrade Thunderbird to 52.4.0 (Closes: #14963).

• Upgrade Tor Browser to 7.0.10 (Closes: #14940).

• Upgrade gdk-pixbuf to 2.36.5-2+deb9u1.0zerotracepen1 (Closes: #14729).

• Minor improvements

• Upgrade to Tor 0.3.1.8-2~d90.stretch+1, a new stable Tor series.

• zerotracepen-documentation: rewrite in Python + use WebKit for display
  instead of the Tor Browser. Since Tor Browser 7.0.8 rendering of
  local pages (like our docs) fail (#14962) so this is probably a
  temporary workaround of that.

• Replace the Unsafe Browser's warning pages with static,
  pure-HTML versions. This is truly a temporary workaround for

  14962.

• Update deb.zerotracepen.boum.org APT repo key (Closes: #14927)

• Refresh Tor Browser AppArmor profile patch to apply on top of
  torbrowser-launcher 0.2.8-4's (Closes: #14923).

• Drop obsolete manual enabling of AppArmor on the kernel
  command-line: it's now enabled by default, so the (Zero Trace Pen -
  Debian) delta gets smaller. 😀

• Bugfixes

• Install Zero Trace Pen Installer 5.0.2. Fixes:

  • Most notably, fix an issue preventing Zero Trace Pen Installer from
    installing to drives containing a non-Zero Trace Pen partition that
    (obviously) has affected a lot of users. (Closes: #14755).
  • Fix an issue that made the resulting installations unbootable
    if Zero Trace Pen Installer was using a too recent udisks2, e.g. the
    one currently in Debian Sid (Closes: #14809).
  • Code clean-ups (Closes: #14721, #14722, #14723).

• Fix UEFI boot for USB sticks installed with Universal USB
  Installer (Closes: #8992).

• Force Tor Browser and Thunderbird to enable accessibility
  support even if no a11y feature is enabled in GNOME yet (Closes:

  14752, #9260).

• Mark our custom Desktop launchers as trusted (Closes: #14793,
  Refs: 14584).

• Add a systemd --user target for bits of GNOME
  EarlyInitialization managed by systemd, and make the keyboard
  layout configuration as part of it. This fixes an issue where
  the layout chosen in the Greeter sometimes wasn't applied in the
  GNOME session (Closes: #12543).

• Build system

• auto/{build,clean,config}: run with set -eu.

• Add script to sanity check the website. Currently it ensures all
  blog posts and security advisories have valid Ikiwiki 'meta
  date' directives, since we depend on it for reproducibility.
  Also make passing this sanity check a pre-condition for building
  the website (Closes: #12726, #14767).

• Abort the ISO build when DKMS modules were not built.

• Take into account where DKMS modules get installed nowadays.

• auto/build: normalize file timestamps in wiki/src before
  building. The copy of the website included in the ISO image has
  "Posted" timestamps that apparently match when we cloned the Git
  repository, which affects reproducibility. (Closes: #14933).

• Fix reproducibility of builds of topic branches that lag behind
  their base branch with the mergebasebranch build option enabled.
  Two otherwise identical merge commits done at different times
  get different IDs, and we happen to embed in the ISO the ID of
  the commit we're building from. (Closes: #14946)

• Test suite

• Bump timeout for "I can save the current page as", otherwise the
  "The Tor Browser directory is usable" scenario fails randomly
  when the system is under load.

• New scenario: installing Zero Trace Pen to an eligible drive with an
  existing filesystem. This is a regression test for #14755.

• New scenario: re-installing over an existing Zero Trace Pen installation.