Hello,

 

 

Pls kindly consider the following words in section 2.6 of RFC5892(for IDNA )

 

2.6.  Exceptions (F)

   F: cp is in {00B7, 00DF, 0375, 03C2, 05F3, 05F4, 0640, 0660,
                0661, 0662, 0663, 0664, 0665, 0666, 0667, 0668,
                0669, 06F0, 06F1, 06F2, 06F3, 06F4, 06F5, 06F6,
                06F7, 06F8, 06F9, 06FD, 06FE, 07FA, 0F0B, 3007,
                302E, 302F, 3031, 3032, 3033, 3034, 3035, 303B,
                30FB}

   This category explicitly lists code points for which the category
   cannot be assigned using only the core property values that exist in
   the Unicode standard.  The values are according to the table below:

PVALID -- Would otherwise have been DISALLOWED

00DF; PVALID     # LATIN SMALL LETTER SHARP S
03C2; PVALID     # GREEK SMALL LETTER FINAL SIGMA
06FD; PVALID     # ARABIC SIGN SINDHI AMPERSAND
06FE; PVALID     # ARABIC SIGN SINDHI POSTPOSITION MEN
0F0B; PVALID     # TIBETAN MARK INTERSYLLABIC TSHEG
3007; PVALID     # IDEOGRAPHIC NUMBER ZERO

 

It means that U+3007 is only allowed as the number zero, otherwise it will not allowed in use in IDNA protocols. 

 

 

 

so it may be not proper that  ?? is regarded as  a variant to 零 based on IDNA protocols.

Best Regards