Date field 'Y'
Deleted Component: xxx-spec
http://www.unicode.org/reports/tr35/#Date_Format_Patterns explains date format patterns. For year 'y', it says "two letters also specifies the maximum length". However, it is not clear that the rule also applies to 'Y' (year in "week of year" based calendar).
Also, LDML specification may address "parse" consideration for two-letter year patterns.
Trac Comment 1 by —2011-05-03T15:54:10.000Z
It looks max-length rule does not apply to 'Y'. So, with pattern 'YY', year 12 will be formatted as "12" and year 2012 will be formatted as "2012".
ISO8601 does not define two-letter year ("YY" represents century... for example, year 2012 with pattern "YY" becomes "20").
It looks two-digit year for week of year is commonly used. With the current specification, there is no way to support this. We should consider either
YY to also indicate the maximum length of 2
new mechanism to specify the maximum length