Client Settings: "Invalid characters" in filename
Filenames for uploading OpenVPN client settings are needlessly limited to alphanumeric characters, dots, dashes and underscores. It means that many uploadable files can be effectively uploaded and must be renamed first.
Linux filesystems allow to use nearly all available characters (only / and NUL are prohibites, some other charactes like * are strongly discouraged). I think that the current limitation is too strict because it avoids to upload files with some commonly used names (such as names with parentheses which are created by web browsers when they save files with colliding names). See the picture below.