The maximum password length that you can set is 128. The maximum characters you can type into the password box to login on the new client is 100. I know it's not a big issue, and clearly not many people have 128 character passwords, but I used to have one. Now I've changed it so I can log in and play lol.
1. I typed my password in and could not log in.
2. Checked where my password stopped, and counted how many characters were missing.
3. Could not go beyond 100 characters in password box.