Hello,

I have a little problem with custom fied (type date). When I  log into the administration with english language everything works fine. But when I logged with Czech language the date is rewited with nonsence after picking the date form the calendar and saving (f.e. I choose 30.06.2021 from calendar, press save and the field id rewitten to 20.06.2030)

Thanks a lot.

Best regards.

Pavel Vit

Pavel,
Think this is all about the default Date Format.  The usual English one is LC2.  Seems that the Czech language files have selected another format.
If  your example the date string in Engish is 30.06.2021 but in the Czech you have 20.06.2030 which is a re-arrangement of 30.06.20 with the century digits added afterwards by the date software.
Colin