The translations (localization) of kde4 PIM (Kontakt / Kmail) are inconsistent. 
While a lot of menu items are translated, local folders, trash, inbox and
outbox sentmail drafts are left in English. 

This has consequences because the denominations of folders in 42.1 (incorrectly
translated) and 42.2 (also incorrectly translated) are inconsistent between the
two. When performing an archive in the 42.1 version it will incorrectly import
to 42.2 because "cartelle locali" (translated) are imported inconsistently in a
separate folder with that name because 42.2 has this folder untranslated (as
local folders). But 13.2 has "bozze" while 42.1 and 42.2 have wrongly "drafts".
Trash folder also jumps from cestino to trash without reason, causing the
creation of such a folder in the wrongly created "cartelle locali" 

Translations should be complete and consistent or the import filter will have
to be adapted in 42.3. 
As it seems impossible to do that (as the translations are every time different
/ inconsistent from 13.2 to 42.1 and to 42.2!), if you want to avoid a very
strong discomfort of your users, when migrating from these versions to kdepim5
in 42.3 (where it will be obligated choice) with troubles using correctly the
otherwise useful migration tool (archiving function), you should fix the
translations in the old versions, or at least make them consistent, in order to
allow a correct archiving and migration to the new version (in case automatic
migration should fail).