De-Branding of Icedove, Reintroduce Thunderbird in Debian
---------------------------------------------------------

Debian and Mozilla has done some new rethinking and talking about the old legal
questions about trademark issues [1].
Based on this revaluation the Debian project got now an agreement from Mozilla
Corp. that the rebranded packages Iceweasel, Debian rebranded version for
Firefox, and Icedove, Debian rebranded version for Thunderbird are no longer
needed.

The maintainers of the Iceweasel package followed that agreement and did a
de-branding of Iceweasel back to Firefox. More information on this process can
be found on [1].
For Icedove the maintainers followed too the new agreement and remove the old
branding after almost 10 years for Icedove and Iceowl-Extension and switched
back to the official branding from Mozilla. The according bug for this process
can be found under [2].

For versions greater 1:45.6.0-2 the following packages were introduced as a
replacement.

old package .... --> new package         usage
---------------------------------------------------------------------------------
icedove ........ --> thunderbird        (Thunderbird Main application)
icedove-dev .... --> thunderbird-dev    (Thunderbird Development files)
icedove-dbg .... --> thunderbird-dbg    (Thunderbird with debugging symbols)
iceowl-extension --> lightning          (Lightning, aka Calendar for Thunderbird)
icedove-l10n-* . --> thunderbird-l10n-* (l10n localization for Thunderbird)
iceowl-l10n-* .. --> lightning-l10n-*   (l10n localization for Lightning)

The old packages were changed to transitional packages and can be safely
removed after the automatically installation of the new packages.

= Profile Migration =
=====================

Due the removing of the rebranding for Icedove Thunderbird will use the default
profile folder $HOME/.thunderbird for storing all the various user related
stuff!
With the new Thunderbird packages there is a wrapper script included, placed as
/usr/bin/thunderbird that will do a adoption of the existing profile folder
$HOME/.icedove into the new default folder for the user profile
$HOME/.thunderbird by setting up a symlink to the existing profile if possible.

The automatism in the script will check the following parts:

  1. Check if there is a folder or a symbolic link $HOME/.icedove existing and
     there is NO folder or symbolic link $HOME/.thunderbird.

  2. Create a symlink from $HOME/.thunderbird to $HOME/.icedove .

  3. Fixing Mime type registration for' http(s)' and 'file' inside mimeTypes.rdf
     if they registered for iceweasel. Before starting the fixup a backup will
     be created name $FILE.backup_thunderbird_migration-${DATE}.

  4. Also check for desktop type registrations of 'userapp-icedove*.desktop' in
     '$HOME/.config/mimeapps.list' and $HOME/.local/share/applications/mimeapps.list,
     but only if this file exists, users of tiling window managers won't have
     this file. Read further for more information on this.
     Like above, a backup of the existing file with same schema will be created
     if needed.

  7. If all was going well, starting Thunderbird.

  8. If there is no folder $HOME/.icedove or $HOME/.thunderbird exists the
     wrapper script will start Thunderbird without any extra action.

  9. The above steps from 3.) will be also done if you already have a symlink
     $HOME/.thunderbird that is pointing to $HOME/.icedove or the opposite,
     $HOME/.thunderbird is pointing to $HOME/.icedove.

     So if you don't have one of the following four cases the wrapper script
     will exit with a error message.

     1. $HOME/.icedove is existing and holds valid profile data
     2. $HOME/.thunderbird points to $HOME/.icedove and 1. is true
     3. $HOME/.icedove points to $HOME/.thunderbird and 1. is true
     4. $HOME/.thunderbird is existing and holds valid profile data
        (Note: Not the script, but Thunderbird will error out here if no
         profiles are found!)

If there is anything going wrong there will be splash screens displayed with
some additional notes, the logger mechanism will write some information about
what's going wrong into /var/log/syslog.

So don't panic if there is something not working automatically. If the starter
script can't do the adoptions you will need to look by yourself and solve the
situation. Mostly there can be already a folder or symlink $HOME/.thunderbird
that prevents a automatic migration by the script. In such a case save a
existing folder $HOME/.thunderbird else where if needed and restart the
Thunderbird application. Other things like extra special mountpoints by the
system administrator can't also be handled by the script. Please ask the
service desk if you have trouble then.

What else can you do?
You can call '/usr/bin/thunderbird --verbose' from a command line to see a
verbose output of the wrapper script. For more options of the wrapper script
and how to use them call '/usr/bin/thunderbird --help'.

The Debian wiki is holding also extra information about the migration of
Icedove to Thunderbird.

  https://wiki.debian.org/Thunderbird

For backward compatibility whithin the Stretch release there will be that
migration functionality until the release of Buster (aka Debian 10).
Afterwards you can still do this on your on by moving the folders manually.

= Avoid the pop-up information about migration globally =
=========================================================

Within some use cases (e.g. bigger company environments) it can sometimes not
be useful that a user will see the dialogue window about the profile migration
as this can be more confusing than helpful.
To avoid this dialogue for all users on the system the administrator can create
a file '/etc/thunderbird/no_migration_popup' and the starting wrapper will
not pop-up the information dialogue if the migration isn't already done.

= User specific MIME Associations =
===================================

The desktop environment (usually Gnome, KDE, Mate etc.) is holding the
specific associations between MIME types and applications in various
places.  In order the user can override system settings and adding new
ones the according place in the users home is the file
'$(HOME)/.config/mimeapps.list'.

The migration is taking care for old 'icedove.desktop' associations and
is rewriting them to 'thunderbird.desktop'.
Like already done for the user profile, there will be always a backup
of the existing file created before the replacement can be done. In case
of problems you can safely move back to the original file. You will lost
then the needed association for the thunderbird binary.

You can call '/usr/bin/thunderbird --show-backup' to see created backups from
the various possible modified files while the profile adoption.

See also:

 https://specifications.freedesktop.org/mime-apps-spec/mime-apps-spec-1.0.html

= Migration of global configurations =
======================================

If you have some own special preferences files placed in '/etc/icedove/pref/'
they will be moved to '/etc/thunderbird/pref/'.
In case you have a modified file '/etc/icedove/pref/icedove.js' it will be
moved to '/etc/thunderbird/pref/icedove.js.dpkg-backup' to keep your changes.
Please adjust this file to the Thunderbird specific configuration file
'/etc/thunderbird/pref/thunderbird.js'. The old folder '/etc/icedove' is gone
be removed only if it is completely empty.

There are still some corner cases where this automatism with configuration
files in /etc/thunderbird/pref is not fully working. Please note #806955 [4]
about such issues.

[1] https://en.wikipedia.org/wiki/Mozilla_software_rebranded_by_Debian
[2] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=815006
[3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=816679
[4] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=806955

 -- Carsten Schoenert <c.schoenert@t-online.de>  Sun, 21 Aug 2016 10:12:00 +0200

Mozilla Crash Reporter for Thunderbird
--------------------------------------

The crash reporter for Thunderbird is enabled since version > 1:45.6.0-3. By
this a possible crash could be automatically send to Mozilla if the user is
accepting this. There is nothing send to Mozilla without a user action. More
information about the crash reporter can be found on:

https://support.mozilla.org/en-US/kb/mozilla-crash-reporter-tb

Please consider to use the crash reporter for getting crashes reported
upstream, this also helps the maintainers if Thunderbird to get crash reports
send upstream.
Submitted crash reports can be found, if any was send, in

  ~/.thunderbird/Crash Reports/submitted/

 -- Carsten Schoenert <c.schoenert@t-online.de>  Sun, 29 Jan 2017 14:15:00 +0100

Icedove for Debian
------------------

Icedove is the Thunderbird email client from Mozilla rebranded by Debian.

Mozilla has changed the kind of developing and managing Thunderbird and make an
announcement about this on July 8 2012. Since this announcement Mozilla decided
to change the focus of there own software development and will put more action
on important web projects and of course on FirefoxOS. Mozilla plans to open the
Thunderbird development to a more community driven project but will also be
there for security and stability maintenance. There are no plans to close the
packaging of Icedove from the Debian side, but the future will see where the
upstream project will go to.
As long as Mozilla will provide ESR versions there will be packaged versions of
those inside the various release of Debian.

 -- Carsten Schoenert <c.schoenert@t-online.de>  Sun, 2 July 2013 21:32:07 +0100

Downgrading TLS security
------------------------

If your provider doesn't support TLS 1.2 and you can't make him
upgrade you can change:

    "security.tls.version.min"

and/or

    "security.tls.version.max"

in about:config (available via "Edit ->> + Preferences -> Advanced ->
General -> Config Editor"). For details see
http://kb.mozillazine.org/Security.tls.version.* .

Note that changing these values decreases your transport level
security. For more details see:

https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS
https://bugzilla.mozilla.org/show_bug.cgi?id=480514
https://wiki.mozilla.org/Security/Server_Side_TLS
http://en.wikipedia.org/wiki/Network_Security_Services
http://kb.mozillazine.org/Connection_errors_-_SMTP
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=761245
https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-00

 -- Carsten Schoenert <c.schoenert@t-online.de>  Wed, 15 Oct 2014 18:38:00 +0200

Adjusting TLS fallback strategy
-------------------------------

Mozilla introduced a new setting with version 34.0b1:

    "security.tls.version.fallback-limit"

The recommended (and default) value currently is: 3 (since 38.0b2)

This means Thunderbird is doing no fall back from TLS 1.2 to 1.1 or to 1.0 at
all if the server is requesting this.
A value of '2' would mean Thunderbird is only using TLS 1.2 and TLS 1.1 as fall
back.
And with a value of '1' Thunderbird would do a fall back down to TLS 1.0 if
needed. A fall back to SSLv2/v3 isn't supported.

Technical details can be found on:
https://bugzilla.mozilla.org/show_bug.cgi?id=1093724
https://bugzilla.mozilla.org/show_bug.cgi?id=1084025

Reactivateing SSLV3 connectivity
--------------------------------

Due to POODLE and BEAST SSLv3 encrypted connections are not considered secure
anymore. See [1], [2] and [3] for details. If you need to reactivate SSLv3 to
use Thunderbird against legacy systems you have to change the settings for

    "security.tls.version.min"

and set the value to '0'.

This setting can be found in the about:config summary.
(available via "Edit ->> + Preferences -> Advanced -> General -> Config Editor").
For details see
http://kb.mozillazine.org/Security.tls.version.* as written above.

Please read also:
[1] http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-3389
[2] https://www.openssl.org/~bodo/ssl-poodle.pdf
[3] https://blog.mozilla.org/security/2014/10/14/the-poodle-attack-and-the-end-of-ssl-3-0/

 -- Carsten Schoenert <c.schoenert@t-online.de>  Wed, 04 Sep 2017 18:11:00 +0100

Plugins and Icedove settings
----------------------------

There are at least one known plugin that conflict with the change of the
security settings from above.
The user Brent S. Elmer has reported that the plugin 'HTTPS Everywhere' from
the Electronic Frontier Foundation is blocking a permanent change of the
setting "security.tls.version.min". Note that this behavior is no Debian
related issue.

Please report other plugins and extensions that doesn't work well with the
security settings.

[1] https://www.eff.org/https-everywhere
[2] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=774790

 -- Carsten Schoenert <c.schoenert@t-online.de>  Sun, 18 Jan 2015 9:34:00 +0100

New and Changed Features with Icedove version 38.x and above
------------------------------------------------------------

At the Thunderbird Summit 2014 in Toronto [1] the contributors and developers
for Thunderbird decided to focus their work on some important changes that now
released with version 38.0.1.
For Icedove these changes means in detail:
 * New storage backend maildir
   You can now choose as backend while set up a new account to store the
   emails in a maildir [2] backend. There is no migration from existing
   accounts into the maildir backend format available! You have to set up a
   new account for that and move your mails!

 * Removing the 4GB folder maximum
   In previous versions you couldn't use more than 4GB within one folder in
   your INBOX, now this limit isn't exist any longer.

 * Searching contacts across all address books
   The address book now contains a folder "All Address Books" from there you
   can search for any address in all of your local or remote address books.

 * Support OAuth backend for new created GMail accounts
   You are now able to use the OAuth authentication while you create a new
   account for a GMail address. Existing accounts can be changed to use
   OAuth.

 * Opt out automatic installation of Lightning
   Mozilla has changed the installation mechanism for Lightning away from a
   always manually installation to a automatic installation with a option to
   opt out this while the main installation of Thunderbird.
   Debian is handling this slightly different as we use a package management
   for such automatism.
   On a Debian system the package iceowl-extensiom (the rebranded Lightning
   package from Mozilla) will now installed automatically if you install or
   upgrade the Icedove package through the package manager you prefer.
   If you already have installed the Lightning package Icedove will use this
   AddOn like before the upgrade.
   But we recommend to not use the Lightning AddOn to work always with full
   compatible program packages. So please remove the Lightning plugin and use
   the iceowl-extension instead. No data will be lost!

[1] https://wiki.mozilla.org/Thunderbird:Summit_2014
[2] https://en.wikipedia.org/wiki/Maildir

 -- Carsten Schoenert <c.schoenert@t-online.de>  Sun, 14 Jun 2015 13:13:00 +0200
