Maintenance days always fall on Mondays of odd-numbered weeks, unless they are holidays or public holidays. In this case, the maintenance work is carried out on the first working day after non-working days and holidays.
February 12, 26
March 11, 25
April 8, 9, 10, 11, 12, 22
May 6 , 21 (Tuesday!)
June 3, 17
July 1, 15, 29
August 12, 26
September 9, 23
October 7, 8, 9, 10, 11, 21
November 4, 18
December 2, 16, 30