For bug 45979, all Vietnamese wikis at the time were switched over to Vietnamese-language category collation. Since then, the Vietnamese Wikivoyage has been created with the default sort order, which is quite inconvenient for Vietnamese speakers.
Switching to Vietnamese collation would be an uncontroversial move, but just in case, I've started a discussion over at [[voy:vi:Wikivoyage:Thảo luận#Thứ tự sắp xếp]].
Once the community expresses its approval there, please set $wgCategoryCollation to 'uca-vi' and rebuild the category sort keys.
Version: wmf-deployment
Severity: enhancement
URL: https://vi.wikivoyage.org/wiki/Wikivoyage:Thảo_luận#Th.E1.BB.A9_t.E1.BB.B1_s.E1.BA.AFp_x.E1.BA.BFp
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=45979