Some time ago, I did some small C# client, and were pretty basic (just to gather my clan's pvp stats, lost interest when I found out I wasn't the best), and back then, i clearly remember that the first endpoint I was using, the Gamertag/PSN ID were case-insensitive. Now, GetMembershipIdByDisplayName is case sensitive so if I use "jpcortesp" it returns a not found, but if I use JPCortesP, it works as expected. Is there any workaround? I don't think alternating case of every char makes sense