These month tokens are used to display only a part of the current month name.
•[M] displays the first letter of the weekday.
•[Mm] and [MM] display all the other letters.
For example, on November 10, in English:
•[M] = N.
•[Mm] = ovember.
•[MM] = OVEMBER.
Using the value of [ddd] instead of [dddd]
To base the conversion of either of the present tokens on the value of the [mmm] token rather than the [mmmm] token, append the :sh modifier to the end of the token. For example: [Mm:sh] and [MM:sh]. The use of [M:sh] is also possible, but it is rarely used, except for languages where the first letter of the month names differs from the short to the full version of the name.