Hello Kostya,
Would it be ok to change
<string name="mail_task_calendar">synchronisiere Kalender</string>
to
<string name="mail_task_calendar">Kalender werden geladen</string>
for consistency with:
<string name="mail_task_contacts">Kontakte werden geladen</string>
Depends on what you want to express with <string name="mail_task_calendar">syncing calendar</string>
Kalender werden geladen means: "Calendars are loading" or "Calendars will be loaded"
while
"synchronisiere Kalender" means "syncing Calendars" or Calendars will be synced"
If you want to express that's there an synchronisation, you should change <string name="mail_task_contacts">Kontakte werden geladen</string>
to
<string name="mail_task_contacts">synchronisiere Kontakte</string>
otherwise you should take
<string name="mail_task_calendar">Kalender werden geladen</string>
<string name="mail_task_contacts">Kontakte werden geladen</string>
Missed two more, sorry
<string name="message_display_read_receipt_subject">Empfangsbestätigung - %1$s</string>
<string name="message_display_read_receipt_body">Dies ist eine Empfangsbestätigung für die E-Mail die Sie an %1$s gesandt haben.</string>
or if you would like to have it shorter:
<string name="message_display_read_receipt_subject">Empfangsbestätigung - %1$s</string>
<string name="message_display_read_receipt_body">Empfangsbestätigung für Ihre E-Mail an %1$s.</string>
Ciao,
Joachim