各种irc的使用情况（主要是使用期限），今天得到了upu的官方答复：
---------------------------
dear mr. roocroft:
since 2002, the validity date for exchange is printed on each international reply coupon.
the new international reply coupon (beijing model 2), on sale from 1 july 2006, is valid for exchange until 31 december 2009.
the international reply coupons (beijing model 1), on sale from 1 january 2002, must be exchanged before 31 december 2006. they will have no value after this date.
i would like to inform you that international reply coupons (ircs) issued from 1906 to 1974 (in blue colour) do not have any value for exchange, but maybe they have an historical value. you may wish to consult a collector of ircs to know if the coupon has any financial value.
you should understand that currently the ircs issued from 1975 to 2001 (in yellow colour) are exchangeable indefinitely according to the current upu rules. however, this kind of irc cannot be anymore exchangeable, in term of finances, between the postal administrations since 30 june 2006. therefore, it means that some of them do not accept anymore this coupon for exchange.
the exchange of irc (after the customer's exchange) between the postal administrations is managed by a bilateral agreement and if there's no bilateral agreement, the postal administrations lose money.
regards
claude voirol
irc and philately programme assistant
de : alan roocroft [mailto:al-mee@aapt.net.au]
envoyé : mardi, 15. août 2006 11:42
À : cri
objet : ircs
