This looks way better than the first attempt:

 - both full and incremental upgrades are added for the existing v2
   boilerplate UDFs, regarding past versions: 4.0, 4.1, 4.1.1, and 4.2;

 - add boilerplate plus full/incremental upgrades for non-existing v2
   UDFs, regarding past versions: 4.0~beta1, 4.0~beta2, and 4.0~rc1;

 - add boilerplate UDFs for this release and the next two ones
   (emergency release and release candidate): 4.2.1, 4.2.2, 4.5~rc1;

 - minor edits (extra quotes around the version) for the existing v2
   boilerplate UDFs, regarding next versions: 4.3, 4.5 (presumably to
   avoid integer/string confusion).

This reverts commit 77fc5d4e.

The release process documentation being followed was buggy, let's start
over.

Currently translated at 39.1% (9 of 23 strings)

Translation: Tails/wiki/src/install/inc/steps/install_with_etcher.inline.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcinstallincstepsinstall_with_etcherinlinepo/es/

wiki/src/news/version_4.2.ar.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.ca.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.id.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.pl.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.ru.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.sr_Latn.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.tr.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.zh.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/news/version_4.2.zh_TW.po: adding as wiki/src/news/version_4.2.de.po has added.
wiki/src/doc/about/features.ar.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.ca.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.id.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.pl.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.ru.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.sr_Latn.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.tr.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.zh.po: updating as wiki/src/doc/about/features.de.po has changed.
wiki/src/doc/about/features.zh_TW.po: updating as wiki/src/doc/about/features.de.po has changed.

Currently translated at 14.8% (4 of 27 strings)

Translation: Tails/wiki/src/install/inc/steps/install_with_gnome_disks.inline.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcinstallincstepsinstall_with_gnome_disksinlinepo/es/

Currently translated at 21.7% (5 of 23 strings)

Translation: Tails/wiki/src/install/inc/steps/install_with_etcher.inline.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcinstallincstepsinstall_with_etcherinlinepo/es/

Currently translated at 100.0% (118 of 118 strings)

Currently translated at 100.0% (37 of 37 strings)

Currently translated at 100.0% (75 of 75 strings)

Currently translated at 71.4% (25 of 35 strings)

Translation: Tails/wiki/src/news/2019-fundraiser.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcnews2019-fundraiserpo/fr/

Currently translated at 71.4% (25 of 35 strings)

Translation: Tails/wiki/src/news/2019-fundraiser.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcnews2019-fundraiserpo/fr/

Currently translated at 13.0% (3 of 23 strings)

Translation: Tails/wiki/src/install/inc/steps/install_with_etcher.inline.*.po
Translate-URL: http://translate.tails.boum.org/projects/tails/wikisrcinstallincstepsinstall_with_etcherinlinepo/es/

Currently translated at 100.0% (77 of 77 strings)