Kleinblatt is closed on those holidays (2018):

   1st of January New year
31st of  March till 7th of April Pessah (jewish easter)
20st of May till 21st of May Shavouoth (jewish pentecost)
29th of July till 19th of August yearly holidays
10th of  September till 11th September Rosh hashana (jewish newyear)
19th of  September Yom kippoer (day of reconciliation)
24th  of September till 25th of September Soekoth (feast of tabernacles)
   1st of October till 2nd October Simchat torah (feast of the bible)