There are two set of rules, one for non-Turkish # Preserve canonical equivalence for I with dot. Turkic is handled below. 0130; 0069 0307; 0130; 0130; # LATIN CAPITAL LETTER I WITH DOT ABOVE And another for Turkish # Turkish and Azeri # I and i-dotless; I-dot and i are case pairs in Turkish and Azeri # The following rules handle those cases. 0130; 0069; 0130; 0130; tr; # LATIN CAPITAL LETTER I WITH DOT ABOVE 0130; 0069; 0130; 0130; az; # LATIN CAPITAL LETTER I WITH DOT ABOVE # When lowercasing, remove dot_above in the sequence I + dot_above, which will turn into i. # This matches the behavior of the canonically equivalent I-dot_above 0307; ; 0307; 0307; tr After_I; # COMBINING DOT ABOVE 0307; ; 0307; 0307; az After_I; # COMBINING DOT ABOVE # When lowercasing, unless an I is before a dot_above, it turns into a dotless i. 0049; 0131; 0049; 0049; tr Not_Before_Dot; # LATIN CAPITAL LETTER I 0049; 0131; 0049; 0049; az Not_Before_Dot; # LATIN CAPITAL LETTER I # When uppercasing, i turns into a dotted capital I 0069; 0069; 0130; 0130; tr; # LATIN SMALL LETTER I 0069; 0069; 0130; 0130; az; # LATIN SMALL LETTER I # Note: the following case is already in the UnicodeData.txt file. # 0131; 0131; 0049; 0049; tr; # LATIN SMALL LETTER DOTLESS I If I understand this correctly, when we test the IDNA behavior of the uppercase string in a Turkish setting we should see the behavior described in the second part. -Dennis From: Latingp <latingp-bounces@icann.org> on behalf of Mats Dufberg <mats.dufberg@internetstiftelsen.se> Date: Thursday, May 14, 2020 at 4:27 PM To: ICANN Latin GP <Latingp@icann.org> Subject: [EXTERNAL] [Latingp] Handling of down casing of I-dotted in Turkish locale The link below goes to the file in the Unicode database that handles the special casing rules for i etc in Turkish and Azerian (sp?). The relevant section is the last section of the file. https://unicode.org/Public/UNIDATA/SpecialCasing.txt<https://secure-web.cisco.com/1dlxHfZjx47yHAT5TJ-TrHDc10FAKGc9NIcXVBJkyDPDxPqAHTonlC3LhAzhf7tuji_ck2p2O599Zho-hT5J6ZLnoqC-tfO5ehsRehGO7ER7h5Nm0pL0UYS053l7GUZP_K23K_ECygicL5k6uDIdW-Mh1dnG-B1Pgqm4-ECoNtGOXM1VYTLHWI8kNdvamKodKRVV6HEH8LbuG3FhAaQQsd3SVJCGdOINew7EywrlX7-oPhyC4b4sidE-XrkW1a4dSdPfxO7mFsAvI4mP3kzPAzg/https%3A%2F%2Funicode.org%2FPublic%2FUNIDATA%2FSpecialCasing.txt> --- Mats Dufberg mats.dufberg@internetstiftelsen.se Technical Expert Internetstiftelsen (The Swedish Internet Foundation) Mobile: +46 73 065 3899 https://internetstiftelsen.se/